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P4 verification: cite Apple's own 1985 LaserWriter Technical Procedures (hosted here) as the source of the two adjustment procedures, with Apple's procedure part numbers
Copyedit (23 em dashes, 89 bold, bold-label lists, self-reference and rebuttal sentences removed); note Apple's own 90.5 F / 34 C mismatch; ammonia-cleaner caution attributed to the LW II and Personal LW sections where Apple prints it; weight wording; local copy of infobox photo
 
(One intermediate revision by the same user not shown)
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{{Infobox computer peripheral
{{Infobox computer peripheral
| name        = Apple LaserWriter
| name        = Apple LaserWriter
| image        = [[File:Laserwriter.jpg|250px]]
| image        = [[File:Laserwriter.jpg|260px|frameless]]
| caption      = Apple LaserWriter
| caption      = Apple LaserWriter
| manufacturer = Apple Computer, Inc.
| manufacturer = Apple Computer, Inc.
| type        = Laser printer
| type        = Laser printer
| interface    = AppleTalk (DB-9), RS-232 (DB-25)
| interface    = AppleTalk (DB-9), RS-232-C (DB-25)
| compatible  = Macintosh; MS-DOS computers via RS-232
| compatible  = Macintosh over AppleTalk; other computers over RS-232-C
| dimensions  = 11.5 in. H x 18.5 in. W x 16.2 in. D (28.2 in. with trays)
| dimensions  = 11.5 in high × 18.5 in wide × 16.2 in deep (28.2 in with trays)
| weight      = 77 lb
| weight      = 77 lb
| power        = 100-115 V AC 60 Hz (domestic); 220-240 V AC 50 Hz (international)
| power        = 100-115 V AC 60 Hz (domestic); 220-240 V AC 50 Hz (international)
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}}
}}
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The '''Apple LaserWriter''' is Apple's first laser printer: a '''Canon LBP-CX''' engine, '''300 dpi''', '''8 pages per minute''', driven by an I/O board carrying Adobe PostScript.<ref name="asg">''Apple Service Guide for LaserWriter Printers, Volume I'', Apple Computer, Inc., January 1992 (072-0631-B) — hosted on this wiki as [[:File:Apple LaserWriter Printers Volume I.pdf]]. Covers the LaserWriter, LaserWriter Plus, LaserWriter II SC/NT/NTX/IIf/IIg and Personal LaserWriter SC/NT/LS. Introductory safety section: the high-voltage, optical-fibre, fuser-cooling, ESD, not-being-grounded and lifting warnings; the LaserWriter Safety Rules; the toner-safety paragraph; the laser-safety paragraph and the three laser warning labels. Tab 2, LaserWriter/LaserWriter Plus: parts list with part numbers (pages 3–4); print engine specifications (page 7); status lights (page 8); service test print and user test print (page 9); the pre-power-on checklist and troubleshooting flowcharts and tables (pages 10–51); the LaserWriter Plus ROM upgrade (pages 52–53); the laser power adjustment (page 54); the image skew adjustment (pages 55–56); and preventive maintenance including the page counter, the maintenance schedule and the Standard Maintenance and 100,000-Page Service checkpoint tables (pages 57–60). Tab 3, LaserWriter II: parts list (pages 4–5); controller-I/O board specifications (page 10); print engine specifications (page 11); status LEDs (page 12); test pages (page 13); the pre-power-on checklist, the IIf/IIg status-LED diagnostic chart and the troubleshooting tables (pages 14–54); the laser power output check (page 55); the NTX memory and ROM upgrades (pages 56–57); the IIf/IIg memory upgrade (page 58); and preventive maintenance (pages 59–60). Tab 6, Ports and Cables: the peripheral cable table, external connector diagrams, connector pin-outs and switch configurations.</ref>
The '''Apple LaserWriter''' is Apple's first laser printer. It uses a Canon LBP-CX print engine at 300 dpi and 8 pages per minute, driven by an I/O board with a 68000 processor and Adobe PostScript.<ref name="asg">''Apple Service Guide for LaserWriter Printers, Volume I'', Apple Computer, Inc., January 1992 (072-0631-B), hosted on this wiki as [[Apple LaserWriter Printers Volume I]] ([[:File:Apple LaserWriter Printers Volume I.pdf|PDF]]). Covers the LaserWriter, LaserWriter Plus, LaserWriter II SC/NT/NTX/IIf/IIg and Personal LaserWriter SC/NT/LS. Introductory safety section: the high-voltage, optical-fibre, fuser-cooling, ESD, not-being-grounded and lifting warnings; the LaserWriter Safety Rules; the toner-safety paragraph; the laser-safety paragraph and the three laser warning labels. Tab 2, LaserWriter/LaserWriter Plus: parts list with part numbers (pages 3-4); print engine specifications (page 7); status lights (page 8); service test print and user test print (page 9); the pre-power-on checklist and troubleshooting flowcharts and tables (pages 10-51); the LaserWriter Plus ROM upgrade (pages 52-53); the laser power adjustment (page 54); the image skew adjustment (pages 55-56); and preventive maintenance including the page counter, the maintenance schedule and the Standard Maintenance and 100,000-Page Service checkpoint tables (pages 57-60). Tab 3, LaserWriter II: parts list (pages 4-5); controller-I/O board specifications (page 10); print engine specifications (page 11); status LEDs (page 12); test pages (page 13); the pre-power-on checklist, the IIf/IIg status-LED diagnostic chart and the troubleshooting tables (pages 14-54); the laser power output check (page 55); the NTX memory and ROM upgrades (pages 56-57); the IIf/IIg memory upgrade (page 58); and preventive maintenance (pages 59-60). Tab 6, Ports and Cables: the peripheral cable table, external connector diagrams, connector pin-outs and switch configurations.</ref> Read the [[#Safety|Safety]] section before working on one: the printer contains an invisible laser, a hot fuser and a high-voltage supply.
 
'''Before you touch one, read the [[#Safety|Safety]] section.''' These machines contain an invisible laser, a fuser hot enough to burn, and a high-voltage supply, and Apple's own rules for working on them are specific.


== Specifications ==
== Specifications ==
Apple's own table:<ref name="asg" />
{| class="wikitable styled-table" style="width:90%;"
{| class="wikitable styled-table" style="width:90%;"
|+'''Print engine specifications'''
|+'''Print engine specifications (Apple Service Guide, Tab 2, p. 7)'''
| '''Marking engine''' || Canon LBP-CX laser xerographic
|-
| Marking engine || Canon LBP-CX laser xerographic
|-
|-
| '''LaserWriter I/O board''' || '''12 MHz 68000''' microprocessor; '''1.5 MB RAM'''; '''512K ROM''' (LaserWriter) and 1 MB ROM (LaserWriter Plus); AppleTalk and RS-232-C interfaces
| LaserWriter I/O board || 12 MHz 68000 microprocessor; 1.5 MB RAM; 512K ROM (LaserWriter) and 1 MB ROM (LaserWriter Plus); AppleTalk and RS-232-C interfaces
|-
|-
| '''Print resolution''' || 300 dots per inch
| Print resolution || 300 dots per inch
|-
|-
| '''Speed''' || 8 pages per minute
| Speed || 8 pages per minute
|-
|-
| '''Paper feed''' || Automatic from paper input cassette; manual single-sheet feed
| Paper feed || Automatic from the paper input cassette; manual single-sheet feed
|-
|-
| '''Print materials''' || Best results with '''16–20 lb''' single-sheet photocopy bond. Can use most letterhead and coloured stock from '''8 to 34 lb'''. Can also use standard medium-weight overhead transparency material. Envelopes and labels supported via manual feed
| Print materials || Best results with 16-20 lb single-sheet photocopy bond; most letterhead and coloured stock from 8 to 34 lb; standard medium-weight overhead transparency material; envelopes and labels by manual feed
|-
|-
| '''Paper capacities''' || Supports '''Letter, Legal, A4 and B5'''. '''Input cassette holds 100 sheets; output tray holds 20 sheets'''
| Paper capacities || Letter, Legal, A4 and B5. Input cassette 100 sheets; output tray 20 sheets
|-
|-
| '''Printable surface''' || Letter 8.0 × 10.92 in.; Legal 6.75 × 13.0 in.; A4 7.41 × 10.86 in.; B5 7.69 × 10.16 in.
| Printable surface || Letter 8.0 &times; 10.92 in; Legal 6.75 &times; 13.0 in; A4 7.41 &times; 10.86 in; B5 7.69 &times; 10.16 in
|-
|-
| '''Physical dimensions''' || Height 11.5 in.; width 18.5 in.; depth 16.2 in. body only, '''28.2 in. with trays'''; weight '''77 lb'''
| Physical dimensions || Height 11.5 in; width 18.5 in; depth 16.2 in (body only), 28.2 in with trays; weight 77 lb
|-
|-
| '''Operating environment''' || 50 to 90.5 °F (10 to 34 °C); humidity 20 to 80 per cent
| Operating environment || 50 to 90.5&nbsp;&deg;F (printed as 10 to 34&nbsp;&deg;C); humidity 20 to 80 per cent
|-
|-
| '''Power requirements''' || 100 to 115 V AC, 60 Hz (domestic); 220 to 240 V AC, 50 Hz (international)
| Power requirements || 100 to 115 V AC, 60 Hz (domestic); 220 to 240 V AC, 50 Hz (international)
|}
|}
<ref name="asg" />


Two figures there are commonly overstated elsewhere. '''The input cassette holds 100 sheets and the output tray 20''', not 250 apiece. And the depth is 16.2 in. only without trays; with them it is '''28.2 in.''', which matters if you are measuring a shelf.
The Celsius figure in Apple's table does not match the Fahrenheit one: 90.5&nbsp;&deg;F is 32.5&nbsp;&deg;C, the figure Apple's pre-power-on checklist uses.<ref name="asg" />
 
Apple's own table gives the processor as '''12 MHz'''.<ref name="asg" /> The often-quoted "11.16 MHz operating speed" could not be traced to an Apple document and is not stated here, nor are wattage, current draw or BTU figures, which do not appear in this guide.


== Safety ==
== Safety ==
Apple's warnings for the LaserWriter family:<ref name="asg" />


Apple's warnings, verbatim in substance:<ref name="asg" />
* The printers operate at high voltages. Switch off and unplug the power cord before servicing, and never work on a LaserWriter under power except when making live adjustments. With the covers off and the power on, do not touch the high-voltage power supply or the DC power supply.
 
* Never disconnect the optical fibre cable or open the laser access hatch with the printer switched on. The beam is infrared: it cannot be seen and can permanently damage the eyes. When servicing or adjusting the optical system, keep screwdrivers and other shiny objects out of the beam, whose reflection is just as dangerous. Warning labels are fitted inside the covers where exposure is possible.
* '''High voltage.''' The LaserWriter printers operate at high voltages. Always switch off and unplug the AC power cord before servicing. Certain parts are electrified when the printer is under power. Never work on a LaserWriter under power '''except when making live adjustments'''.
* The fuser rollers become very hot. Switch the printer off for at least five minutes before servicing the fuser assembly.
* '''Laser.''' '''Never disconnect the optical fibre cable or open the laser access hatch when the printer is switched on.''' The optical fibre carries the infrared laser beam, '''which you cannot see but which can permanently damage your eyes'''. When servicing or adjusting the optical system, '''do not place screwdrivers or other shiny objects in the path of the beam''' — the reflected beam is just as dangerous. Warning labels are attached inside the covers where there is a danger of exposure.
* Do not be grounded when working on plugged-in equipment or making live adjustments, and remove all jewellery before starting.
* '''Fuser.''' The fuser assembly rollers become very hot in operation. '''Switch the printer off for at least five minutes before servicing the fuser assembly''' to let the rollers cool.
* The I/O boards contain CMOS parts that are very sensitive to static and skin acid. Handle chips, ROMs and SIMMs by their edges, do not touch anyone working on integrated circuits, and keep polyester clothing, plastic, vinyl and polystyrene out of the work area.
* '''Do not touch''', with the covers off and the printer powered: the high-voltage power supply, or the DC power supply.
* Apple's safety section gives LaserWriter printers as weighing from 32 to 60 pounds; its specification table gives this model as 77 lb. Take care when lifting.
* '''Do not be grounded''' when working on plugged-in equipment or performing live adjustments. '''Remove all jewellery before starting''' — removing these conductors reduces the possibility of electric shock.
* Toner is a non-toxic mixture of plastic, iron and a little pigment. Remove it from skin and clothing with a dry tissue and wash with cold water; hot water makes it gel and fuse into fabric. Toner attacks vinyl.
* '''ESD.''' LaserWriter I/O boards contain CMOS components, among the most sensitive chips in use. CMOS chips, ROMs and SIMMs are very susceptible to electrostatic discharge and skin-acid damage. '''Handle them only by the edges.''' Do not touch anybody who is working on integrated circuits; do not wear polyester clothing or bring plastic, vinyl or polystyrene into the work area.
* '''Weight.''' LaserWriter printers weigh from 32 to 60 pounds; this one is 77 lb. Be careful lifting.
* '''Toner''' is a non-toxic substance of plastic, iron and a little pigment. Remove as much as possible from skin and clothing with a dry tissue, then wash with '''cold''' water — hot water gels it and fuses it permanently into fabric. '''Toner attacks vinyl''', so keep it off vinyl surfaces.
* '''Never use an ammonia-based cleaner''' on a LaserWriter; it discolours the plastic.<ref name="asg" />


== Status Lights ==
Apple's guide also cautions against ammonia-based cleaners on the LaserWriter II and Personal LaserWriter, because they discolour the plastic, and its LaserWriter checklist asks whether the printer is exposed to ammonia gas.<ref name="asg" />


'''There are four, not three''', and one of them is not on the front panel:<ref name="asg" />
== Status lights ==
The LaserWriter has three status lights on the front display panel and a Test light on the rear I/O connector plate.<ref name="asg" />


{| class="wikitable styled-table" style="width:90%;"
{| class="wikitable styled-table" style="width:90%;"
|+'''LaserWriter status lights'''<ref name="asg" />
|+'''LaserWriter status lights'''
! Light !! Where !! Colour !! Behaviour
! Light !! Position !! Behaviour
|-
|-
| '''Ready/Wait''' || Front display panel || Green || Flashes during warm-up; stays on continuously when ready to print
| Ready/Wait (green) || Front panel || Flashes during warm-up; on continuously when ready to print
|-
|-
| '''Paper-Out''' || Front display panel || '''Yellow''' || On and steady when out of paper or the cassette is not installed. '''Flashes when the printer is preparing to print a page.''' In manual feed mode, stays on steadily if there is no paper on the manual feed tray
| Paper-Out (yellow) || Front panel || On and steady when out of paper or when the cassette is not installed; flashes while the printer prepares to print a page. In manual feed mode, on steadily if there is no paper on the manual feed tray
|-
|-
| '''Paper Jam''' || Front display panel || Red || Comes on when paper jams inside the printer and stays on until the jam is cleared
| Paper Jam (red) || Front panel || On when paper jams inside the printer, until the jam is cleared
|-
|-
| '''Test''' || '''Rear I/O connector plate''' || — || Comes on steady or flashing '''if an error condition exists with the I/O board'''. If the I/O board is working, the Test light '''flashes once and then turns off''' when the printer is switched on
| Test || Rear I/O connector plate || On, steady or flashing, if there is an error condition on the I/O board. With a working I/O board it flashes once at switch-on and then goes out
|}
|}
<ref name="asg" />


'''There is no "Service" LED.''' The Paper-Out light is yellow, not amber, and the fourth light is on the back. The Test light's single flash at power-on is a genuine go/no-go check on the I/O board and costs nothing to observe.
== Test prints ==
 
The two test prints check different halves of the printer.<ref name="asg" />
== Test Prints ==
 
Two different prints, testing two different halves of the machine. Knowing which is which halves the diagnostic problem immediately.<ref name="asg" />
 
=== Service test print — tests the print engine ===
'''Place a jumper between pins J205-1 and J205-2 on the DC controller PCB.'''<ref name="asg" /> This confirms the operation of the print engine, and is what you use to isolate print-engine failures from I/O board failures.
 
=== User test print — tests the I/O board ===
Produced '''each time the printer is switched on''', unless the protocol switch is set to "Special" or the function has been turned off with PostScript software.<ref name="asg" /> It confirms the I/O board works and reports:


* The revision number of the installed PostScript ROMs
The service test print checks the print engine alone. Produce it by jumpering pins J205-1 and J205-2 on the DC controller PCB; it separates print-engine faults from I/O board faults.<ref name="asg" />
* The selected operating mode — PostScript or Diablo 630 emulation
* '''The number of pages the I/O board has produced'''


'''So: a fault that appears on a service test print is in the engine; a fault that appears only on a user test print or when printing from the Macintosh is in the I/O board or beyond it.'''
The user test print is produced each time the printer is switched on, unless the protocol switch is set to "Special" or the print has been turned off with PostScript software. It confirms that the I/O board works and shows the revision of the PostScript ROMs, the selected mode (PostScript or Diablo 630 emulation) and the number of pages the I/O board has produced.<ref name="asg" />


== Ports and Switches ==
A fault that appears on the service test print is in the engine. A fault that appears only on the user test print, or only when printing from a computer, is in the I/O board or beyond it.<ref name="asg" />


The rear panel carries a '''9-pin socket''', a '''25-pin socket''' and a '''4-position mode switch''' marked AppleTalk, Special, 9600 and 1200.<ref name="asg" />
== Ports and switches ==
The rear panel has a 9-pin connector, a 25-pin connector and a four-position mode switch marked AppleTalk, Special, 9600 and 1200.<ref name="asg" />


{| class="wikitable styled-table" style="width:65%;"
{| class="wikitable styled-table" style="width:65%;"
|+'''AppleTalk connector — DB-9 male'''<ref name="asg" />
|+'''AppleTalk connector, DB-9'''
! Pin !! Signal !! Description
! Pin !! Signal !! Description
|-
|-
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| 4 || TXD+ || Transmit data +
| 4 || TXD+ || Transmit data +
|-
|-
| 5 || TXD− || Transmit data −
| 5 || TXD&minus; || Transmit data &minus;
|-
|-
| 8 || RXD+ || Receive data +
| 8 || RXD+ || Receive data +
|-
|-
| 9 || RXD− || Receive data −
| 9 || RXD&minus; || Receive data &minus;
|}
|}
<ref name="asg" />


The mode switch set to '''"AppleTalk"''' selects this port.<ref name="asg" />
Setting the mode switch to AppleTalk selects this port.<ref name="asg" />


{| class="wikitable styled-table" style="width:65%;"
{| class="wikitable styled-table" style="width:65%;"
|+'''RS-232 connector — DB-25 male'''<ref name="asg" />
|+'''RS-232 connector, DB-25'''
! Pin !! Signal !! Description
! Pin !! Signal !! Description
|-
|-
Line 134: Line 119:
| 20 || DTR || Data terminal ready
| 20 || DTR || Data terminal ready
|}
|}
<ref name="asg" />


The mode switch set to '''"1200" or "9600"''' selects this port.<ref name="asg" /> '''Those are the two serial rates the switch offers'''; a figure of 19,200 baud does not appear in Apple's own tables and is not stated here.
Setting the switch to 1200 or 9600 selects the RS-232 port at that rate. The AppleTalk cable is Apple's LocalTalk Connector Kit, DB-9, part number 590-0254 or 630-8272, model M2065.<ref name="asg" />
 
The AppleTalk cable is Apple's '''LocalTalk Connector Kit, DB-9''', part number 590-0254 or 630-8272, model M2065.<ref name="asg" />


== Troubleshooting ==
== Troubleshooting ==
=== Pre-power-on checklist ===
=== Pre-power-on checklist ===
Apple's list of things to confirm before chasing a fault:<ref name="asg" />
Apple's checklist before chasing a fault:<ref name="asg" />
 
* Line voltage 115 V AC &plusmn;10%
* Line voltage is OK — '''115 V AC ±10%'''
* Printer on a solid, level surface
* Printer is installed on a solid, level surface
* Room temperature 50-90&nbsp;&deg;F (10-32.5&nbsp;&deg;C) and humidity 20% to 80%
* Room temperature is between '''50–90 °F (10–32.5 °C)''' and humidity between 20% and 80%
* Printer not in an excessively hot, humid or dusty place or near open flames
* Printer is not in an excessively hot or humid area, near open flames, or in a dusty location
* Printer not exposed to ammonia gas (produced by diazo copiers or cleaning solutions)
* '''Printer is not exposed to ammonia gas''' (produced by diazo copiers or cleaning solutions)
* Printer out of direct sunlight and in a well-ventilated area
* Printer is not in direct sunlight, and is in a well-ventilated area
* Cables and connectors OK
* Cables and connectors are OK
* Toner cartridge installed and OK; replace it if the indicator is red
* '''Toner cartridge is installed and OK''' — replace if the indicator is red
* Fuser roller cleaner felt in place and not dirty
* '''Fuser roller cleaner felt is in place and not dirty'''
* Print density dial set correctly
* Print density adjustment dial is set correctly
* Protocol selector switch on the back set to AppleTalk
* '''Protocol selector switch on the back is set to AppleTalk'''
* Paper cassette loaded to no more than 10 mm high
* Paper cassette is properly loaded — '''not more than 10 mm high'''
* Paper 16-21 lb standard photocopier paper
* Paper is '''16–21 lb''' standard photocopier paper
* Transfer corona wire clean and unbroken
* '''Transfer corona wire is clean and unbroken'''
* Separation belt free of nicks and not broken
* '''Separation belt is OK''' — check for nicks or a broken belt


The ammonia item is not a curiosity. Diazo copiers and some cleaning products produce it, and it will degrade the machine.
=== Diagnostic sequence ===
Apple's order is the pre-power-on checklist, then the LaserWriter Functional Check, then the LaserWriter Print Engine Check, then the lettered troubleshooting tables.<ref name="asg" /> The functional check starts by switching the printer off, waiting one minute, switching it on and waiting three minutes for a user test print; if that is good, it sends a file from a Macintosh over AppleTalk.<ref name="asg" />


=== The diagnostic sequence ===
The tables cover: A, no power; B, delivery rollers do not rotate; D, heater bulb does not operate; E, cannot feed paper manually; F, jams detected when there are none; G, paper jams not detected; H, Paper-Out light on when there is paper; J, preconditioning lamps do not light; K, laser/scanner malfunction; L, erroneous low-toner indication; M, print quality problems; N, paper transport problems.<ref name="asg" />
Apple's order is fixed: '''pre-power-on checklist → LaserWriter Functional Check → LaserWriter Print Engine Check → the numbered troubleshooting tables'''.<ref name="asg" /> The functional check starts by switching the printer off, waiting one minute, switching it on and waiting three minutes for a user test print; if that is good, it then sends a file from a Macintosh over AppleTalk.<ref name="asg" />
 
The tables the flowcharts hand off to include: '''A''' no power; '''B''' delivery rollers do not rotate; '''D''' heater bulb does not operate; '''E''' cannot feed paper manually; '''F''' jams detected when there are no jams; '''G''' paper jams are not detected; '''H''' Paper-Out LED lights when there is paper; '''J''' preconditioning lamps do not light; '''K''' laser/scanner malfunction; '''L''' erroneous low-toner indicator; '''M''' print quality problems; '''N''' paper transport problems.<ref name="asg" />


== Adjustments ==
== Adjustments ==
=== Laser power adjustment ===
=== Laser power adjustment ===
Requires a laser power checker and a digital multimeter.<ref name="asg" />
This needs a laser power checker and a digital multimeter.<ref name="asg" />
 
# Remove the top cover, the I/O board and the card cage.
# Remove the top cover, the I/O board and the card cage.
# '''With the power switched off''', open the laser access hatch and insert the laser power checker with the detector facing the laser diode. '''Make sure it is fully inserted so that no laser light can escape from the access hatch.'''
# With the power off, open the laser access hatch and insert the laser power checker with the detector facing the laser diode. Insert it fully so that no laser light can escape from the hatch.
# Connect the checker's black lead to the meter's "Common" socket and the red lead to "Volts". Set the meter to '''volts, 200 mV range'''.
# Connect the checker's black lead to the meter's common socket and the red lead to volts, and set the meter to the 200 mV range.
# '''Disconnect J209''' from the DC controller board and jumper '''J209-5 to J209-6'''.
# Disconnect J209 from the DC controller board and jumper J209-5 to J209-6.
# Turn '''VR202''' on the DC controller board fully counter-clockwise, to its lowest setting.
# Turn VR202 on the DC controller board fully anticlockwise.
# Switch on and wait until the green Ready/Wait light stops flashing.
# Switch on and wait until the green Ready/Wait light stops flashing.
# '''Briefly''' jumper '''J209-6 to J209-7'''. Remove the jumper and record the reading. Repeat twice more.
# Briefly jumper J209-6 to J209-7, remove the jumper and record the reading. Repeat twice more.
# Average the three readings and compare with the figure on the laser label — '''the voltage printed next to "300", ±1 millivolt'''.
# Average the three readings and compare the result with the voltage printed next to "300" on the laser label; it should be within &plusmn;1 mV.


If the output is low, remove the J209-6/J209-7 jumper, turn VR202 slightly '''clockwise''' and repeat. If high, turn it slightly '''counter-clockwise''' and repeat.<ref name="asg" />
If the output is low, remove the J209-6/J209-7 jumper, turn VR202 slightly clockwise and repeat; if it is high, turn VR202 slightly anticlockwise and repeat.<ref name="asg" />


=== Image skew adjustment ===
=== Image skew adjustment ===
'''Check first:''' produce a user test print and measure from the top left and right corners of the test pattern to the top edge of the paper. '''The difference should be no more than 1 millimetre.'''<ref name="asg" />
To check the skew, produce a user test print and measure from the top left and right corners of the test pattern to the top edge of the paper. The two measurements should differ by no more than 1 mm.<ref name="asg" />


To adjust:<ref name="asg" />
To adjust it:<ref name="asg" />
# Remove the top cover and the I/O board. Switch on and wait for the green Ready/Wait light to stop flashing.
# Remove the top cover and the I/O board. Switch on and wait for the green Ready/Wait light to stop flashing.
# Generate a service test print by briefly jumpering '''J205-1 to J205-2'''.
# Produce a service test print by briefly jumpering J205-1 to J205-2.
# Loosen the four large mounting screws on the scanner unit and the '''two sealed screws closest to the laser unit'''.
# Loosen the four large mounting screws on the scanner unit and the two sealed screws closest to the laser unit.
# '''Rotate the scanner unit around Screw A.''' Clockwise makes the horizontal line incline counter-clockwise; counter-clockwise makes it incline clockwise.
# Rotate the scanner unit around screw A. Clockwise inclines the horizontal line anticlockwise; anticlockwise inclines it clockwise.
# Reprint and remeasure until the difference is 1 mm or less.
# Reprint and remeasure until the difference is 1 mm or less.
# If you run out of travel: tighten the two sealed screws nearest the laser unit, loosen the two on the other side, and rotate around '''Screw B''' instead.
# If you run out of travel, tighten the two sealed screws nearest the laser unit, loosen the two on the other side and rotate around screw B.
 
== Preventive Maintenance ==


== Preventive maintenance ==
=== Reading the page count ===
=== Reading the page count ===
The user test print gives the number of pages printed '''since the installation of the I/O board''' — accurate only if the board has never been repaired or upgraded.<ref name="asg" /> If it has, Apple gives a hardware method:<ref name="asg" />
The user test print gives the number of pages printed since the I/O board was installed, which is the machine's page count only if that board has never been replaced or upgraded.<ref name="asg" /> Otherwise, remove the top cover, the I/O board and the DC controller board, and find the page counter in the middle of the preconditioning exposure assembly, just below the DC controller board. It looks like a small thermometer, and each mark represents about 10,000 pages.<ref name="asg" />
 
# Remove the top cover, the LaserWriter I/O board and the DC controller board.
# Locate the '''preconditioning exposure assembly''', just below the DC controller board.
# The '''page counter''' is in the middle of it and '''looks like a small thermometer'''.
# '''Each mark on the counter represents approximately 10,000 pages.'''


=== Apple's schedule ===
=== Apple's schedule ===
{| class="wikitable styled-table" style="width:80%;"
{| class="wikitable styled-table" style="width:80%;"
|+'''Preventive maintenance schedule'''<ref name="asg" />
|+'''Preventive maintenance schedule'''
! Number of pages !! Procedure
! Pages !! Procedure
|-
|-
| Zero to 50,000 || Standard Maintenance
| 0 to 50,000 || Standard Maintenance
|-
|-
| 50,000 to 100,000 || Standard Maintenance, '''and replace the ozone filter'''
| 50,000 to 100,000 || Standard Maintenance, and replace the ozone filter
|-
|-
| 100,000 to 150,000 || '''100,000-Page Service''', and replace the separation belt
| 100,000 to 150,000 || 100,000-Page Service, and replace the separation belt
|}
|}
<ref name="asg" />


'''Standard Maintenance checkpoints:'''<ref name="asg" /> open and close the toner cartridge's light-blocking shutters to check they are not jammed or broken; clean the cartridge's primary corona wire with the wire brush supplied with the printer; clean the protective shield with a damp cloth; '''do not clean the photosensitive drum unless absolutely necessary''' and, if you must, use a soft cloth saturated with toner powder; replace the fuser roller cleaner felt if dirty; clean the separation claws, delivery guide, separation guide and paper guide with isopropyl alcohol; clean the transfer corona assembly and separation belt with a cotton swab; clean the feeder rollers, separation rollers, transfer guides and feeder guide with isopropyl alcohol; '''replace the ozone filter every 50,000 pages'''.
Standard Maintenance: open and close the toner cartridge's light-blocking shutters to check they are not jammed or broken; clean the cartridge's primary corona wire with the wire brush supplied with the printer; clean the protective shield with a damp cloth; clean the photosensitive drum only if absolutely necessary, with a soft cloth saturated with toner powder; replace the fuser roller cleaner felt if it is dirty; clean the separation claws, delivery guide, separation guide and paper guide with isopropyl alcohol; clean the transfer corona assembly and separation belt with a cotton swab; clean the feeder rollers, separation rollers, transfer guides and feeder guide with isopropyl alcohol; and replace the ozone filter every 50,000 pages.<ref name="asg" />
 
'''100,000-Page Service:'''<ref name="asg" /> clean the fan with a small brush; clean the registration shutter rollers with isopropyl alcohol; and '''replace''' the preconditioning exposure assembly, the grounding spring, the paper pickup rollers, the paper feed rollers and the lower paper feed guide, the fuser assembly, the ozone filter and the separation belt.


'''The fuser is a 100,000-page item, not a 200,000-page item''', and '''the ozone filter is a real consumable''' that is frequently never changed at all.
The 100,000-Page Service adds cleaning the fan with a small brush and the registration shutter rollers with isopropyl alcohol, and replacing the preconditioning exposure assembly, the grounding spring, the paper pickup rollers, the paper feed rollers and lower paper feed guide, the fuser assembly, the ozone filter and the separation belt.<ref name="asg" />


=== Before starting ===
Before starting, switch off and unplug the printer, let the fuser rollers cool, take ESD precautions and lay a drop cloth to protect the floor from grease and toner.<ref name="asg" />
Power off and unplug; '''allow the fuser assembly rollers to cool'''; prepare for ESD; and spread a drop cloth to protect the floor from grease and spilled toner.<ref name="asg" />


== Parts ==
== Parts ==
Selected entries from Apple's parts list:<ref name="asg" />
Selected entries from Apple's parts list:<ref name="asg" />


Line 232: Line 201:
! Part !! Number
! Part !! Number
|-
|-
| DC Controller PCB || 661-0267
| DC controller PCB || 661-0267
|-
|-
| DC Power Supply/Motor Drive PCB, 110 V || 661-0273
| DC power supply/motor drive PCB, 110 V || 661-0273
|-
|-
| DC Power Supply/Motor Drive PCB, 220 V || 661-0274
| DC power supply/motor drive PCB, 220 V || 661-0274
|-
|-
| High-Voltage Power Supply || 661-0266
| High-voltage power supply || 661-0266
|-
|-
| Laser Unit || 661-0277
| Laser unit || 661-0277
|-
|-
| Scanner Unit, 300 DPI || 661-0278
| Scanner unit, 300 dpi || 661-0278
|-
|-
| '''LaserWriter I/O PCB''' || '''661-0436'''
| LaserWriter I/O PCB || 661-0436
|-
|-
| Fuser Assembly, 115 V || 661-0450
| Fuser assembly, 115 V || 661-0450
|-
|-
| Fuser Assembly, 220 V || 699-0318
| Fuser assembly, 220 V || 699-0318
|-
|-
| Power Interlock Assembly, 110 V || 699-0324
| Power interlock assembly, 110 V || 699-0324
|-
|-
| Power Interlock Assembly, 220 V || 699-0325
| Power interlock assembly, 220 V || 699-0325
|-
|-
| AC Driver PCB, 110 V || 661-0268
| AC driver PCB, 110 V || 661-0268
|-
|-
| AC Driver PCB, 220 V || 661-0269
| AC driver PCB, 220 V || 661-0269
|-
|-
| '''Paper Separator Belt''' || 970-1005
| Paper separator belt || 970-1005
|-
|-
| '''Ozone Filter''' || 970-1001
| Ozone filter || 970-1001
|-
|-
| Transfer Corona Assembly || 970-1021
| Transfer corona assembly || 970-1021
|-
|-
| Fan, 110 V 60 Hz || 720-0502
| Fan, 110 V 60 Hz || 720-0502
Line 268: Line 237:
| Fan, 220 V 50 Hz || 970-1074
| Fan, 220 V 50 Hz || 970-1074
|-
|-
| Main Drive Motor || 970-1009
| Main drive motor || 970-1009
|-
|-
| Preconditioner Exposure PCB || 970-1020
| Preconditioner exposure PCB || 970-1020
|-
|-
| Registration Shutter Assembly || 699-0323
| Registration shutter assembly || 699-0323
|-
|-
| Separation/Feed Roller Assembly || 970-1019
| Separation/feed roller assembly || 970-1019
|-
|-
| Display Panel Assembly || 970-1109
| Display panel assembly || 970-1109
|-
|-
| LaserWriter Configuration Block || 750-0102
| LaserWriter configuration block || 750-0102
|}
|}


Note that the DC power supply, AC driver PCB, fuser assembly and fan are all '''different parts for 110 V and 220 V machines'''.<ref name="asg" /> Fitting the wrong one is a real and expensive mistake.
The DC power supply, AC driver PCB, power interlock, fuser assembly and fan all have different part numbers for 110 V and 220 V machines.<ref name="asg" />


== Service Manual ==
== Service manual ==
<pdf>File:Apple LaserWriter Printers Volume I.pdf</pdf>
<pdf>File:Apple LaserWriter Printers Volume I.pdf</pdf>


== Other documentation on this wiki ==
== Other documentation on this wiki ==
* [[Service Support Tranning Programs Laserwriter Technical Procedures Jan 1985]]: Apple's ''LaserWriter Printer Technical Procedures'', the earliest service document for this printer held here, marked on its contents page as "a preliminary version ... for internal use only", with sections stamped rev. Jan 85 and rev. Feb 85. It gives the two adjustments above under their Apple procedure numbers (Laser Power Adjustment, P/N 011-7052; Image Skew Adjustment, P/N 011-7051), a theory of operation (300 dpi, 6.8 million dots per page; the I/O board is a 68000 with 1.5 MB of RAM and 500 KB of ROM), a full take-apart including the fuser assembly, part 699-0306, image-defect and electromechanical troubleshooting tables, and an appendix of DC controller board signals and connectors.<ref name="lwtp85">Apple Computer, ''Apple LaserWriter Printer Technical Procedures'', preliminary version for internal use only, sections stamped rev. Jan 85 and rev. Feb 85. Held on this wiki inside the Service Support Training Programs binder scan, described at [[Service Support Tranning Programs Laserwriter Technical Procedures Jan 1985]] ([[:File:Service_Support_Tranning_Programs_Laserwriter_Technical_Procedures_Jan_1985.pdf]]).</ref> The same binder also contains Apple's Macintosh Office (AppleTalk), DuoDisk and UniDisk technical procedures, ImageWriter and Scribe parts lists, and extracts from the Lisa troubleshooting guide.<ref name="lwtp85" />
* [[Envelope Feeder Service Source]]: Apple's service manual for the LaserWriter envelope feeder. The Pro 600/630 feeder fits only that printer; the 16/600 PS feeder fits both. The manual gives three ways to tell them apart (two-piece or one-piece roller shafts, controller board RG5-0576 or RG1-3437, serial prefix JXC or LBK) and the 1.5 mm separation-guide gap to reset after a strip-down.
* [[Service Training Introduction To Laser Printer Service Version 1.0.1 1996]]: Apple's technician course on the diagnostic method for laser printers. The [[Service Training Introduction To Laser Printer Service Version 1.0 1992|1992 edition]] includes the final test.
* [[The Laser Writer Family 1992]]: Michael Fraase's ''Rapid Reference Guide to The LaserWriter Family'' (Business One Irwin, 1992), a third-party user guide to the Personal LaserWriter LS and NT and the LaserWriter IIf and IIg, with no schematics, parts list or FRU numbers.
* [[Inside The Apple Laserwriter 1989]]: Roger Hart, Scott, Foresman and Company, 1989, 313 pages. A third-party book on using and programming the LaserWriter (PostScript, fonts, page description), with no service procedures, parts or schematics.
* [[Apple Laserwriter Reference 0-201-19258-6 1988]]: Apple's reference for the LaserWriter, LaserWriter Plus, II NT and II NTX, including the printer switch settings and font behaviour.


* '''[[Service Support Tranning Programs Laserwriter Technical Procedures Jan 1985]]''' — '''Apple's
== Related pages ==
  own ''LaserWriter Printer Technical Procedures''''', the earliest service document for this printer
  held here, marked on its own contents page as "a preliminary version … for internal use only" with
  sections stamped rev. Jan 85 and rev. Feb 85. It is the source of the two adjustments above under
  their Apple procedure numbers — '''Laser Power Adjustment P/N 011-7052''' and '''Image Skew
  Adjustment P/N 011-7051''' — and it carries a theory of operation (300 dpi, 6.8 million dots per
  page; the I/O board is a 68000 with '''1.5 MB of RAM and 500 KB of ROM'''), a full take-apart
  including the '''fuser assembly, part 699-0306''', image-defect and electromechanical
  troubleshooting tables, and an appendix of '''DC controller board signals and connectors'''.<ref name="lwtp85">Apple Computer, ''Apple LaserWriter Printer Technical Procedures'', preliminary version for internal use only, sections stamped rev. Jan 85 and rev. Feb 85. Held on this wiki inside the Service Support Training Programs binder scan, described at [[Service Support Tranning Programs Laserwriter Technical Procedures Jan 1985]] ([[:File:Service_Support_Tranning_Programs_Laserwriter_Technical_Procedures_Jan_1985.pdf]]).</ref>
  The same binder also contains Apple's '''Macintosh Office (AppleTalk) Technical Procedures''',
  '''DuoDisk''' and '''UniDisk''' technical procedures, ImageWriter and Scribe parts lists, and
  extracts from the Lisa troubleshooting guide.<ref name="lwtp85" />
 
* '''[[Envelope Feeder Service Source]]''' — Apple's service manual for the '''LaserWriter envelope feeder'''. Two incompatible feeders exist: the Pro 600/630 feeder fits only that printer, the 16/600 PS feeder fits both. The manual gives three independent ways to tell them apart (two-piece versus one-piece roller shafts, controller board RG5-0576 versus RG1-3437, serial prefix JXC versus LBK) and the '''1.5 mm separation-guide gap''' that must be reset after a strip-down.
* '''[[Service Training Introduction To Laser Printer Service Version 1.0.1 1996]]''' — Apple's own technician course. Teaches the diagnostic method rather than a model: establish the deviation from normal operation, act, verify. Its 1996 prerequisites are Apple's own statement of the minimum competence for this work — measure voltage and resistance with a digital multimeter, and read wiring and schematic diagrams. The '''[[Service Training Introduction To Laser Printer Service Version 1.0 1992|1992 edition]]''' still carries the Final Test.
* '''[[The Laser Writer Family 1992]]''' — '''not an Apple document'''. Michael Fraase's ''Rapid Reference Guide to The LaserWriter Family'' (Business One Irwin, 1992), a user-level guide to the Personal LaserWriter LS and NT and the LaserWriter IIf and IIg, distributed "as is, without warranty". No schematic, no parts list, no FRU numbers.
 
== Other LaserWriter books on this wiki ==
* [[Inside The Apple Laserwriter 1989]] - Roger Hart, Scott, Foresman and Company, 313 pages, 1989. A third-party book about '''using and programming''' the LaserWriter: PostScript, fonts and page description. It contains no service procedures, no parts, no schematics and no component values, so it should not be cited for a hardware figure.
* [[Apple Laserwriter Reference 0-201-19258-6 1988]] - Apple's own reference for the LaserWriter, LaserWriter Plus, IINT and IINTX. Cite it for the '''printer switch settings''' and font behaviour.
 
== See Also ==
* [[Apple LaserWriter Plus]]
* [[Apple LaserWriter Plus]]
* [[Apple LaserWriter II NT]]
* [[Apple LaserWriter II NT]]
Line 316: Line 270:


== References ==
== References ==
<references />
<references />


Latest revision as of 14:42, 30 September 2026

Apple LaserWriter
Apple LaserWriter
Manufacturer Apple Computer, Inc.
Type Laser printer
Interface AppleTalk (DB-9), RS-232-C (DB-25)
Compatible Macintosh over AppleTalk; other computers over RS-232-C
Dimensions 11.5 in high × 18.5 in wide × 16.2 in deep (28.2 in with trays)
Weight 77 lb
Model M0180
Power 100-115 V AC 60 Hz (domestic); 220-240 V AC 50 Hz (international)

The Apple LaserWriter is Apple's first laser printer. It uses a Canon LBP-CX print engine at 300 dpi and 8 pages per minute, driven by an I/O board with a 68000 processor and Adobe PostScript.[1] Read the Safety section before working on one: the printer contains an invisible laser, a hot fuser and a high-voltage supply.

Specifications

[edit | edit source]
Print engine specifications (Apple Service Guide, Tab 2, p. 7)
Marking engine Canon LBP-CX laser xerographic
LaserWriter I/O board 12 MHz 68000 microprocessor; 1.5 MB RAM; 512K ROM (LaserWriter) and 1 MB ROM (LaserWriter Plus); AppleTalk and RS-232-C interfaces
Print resolution 300 dots per inch
Speed 8 pages per minute
Paper feed Automatic from the paper input cassette; manual single-sheet feed
Print materials Best results with 16-20 lb single-sheet photocopy bond; most letterhead and coloured stock from 8 to 34 lb; standard medium-weight overhead transparency material; envelopes and labels by manual feed
Paper capacities Letter, Legal, A4 and B5. Input cassette 100 sheets; output tray 20 sheets
Printable surface Letter 8.0 × 10.92 in; Legal 6.75 × 13.0 in; A4 7.41 × 10.86 in; B5 7.69 × 10.16 in
Physical dimensions Height 11.5 in; width 18.5 in; depth 16.2 in (body only), 28.2 in with trays; weight 77 lb
Operating environment 50 to 90.5 °F (printed as 10 to 34 °C); humidity 20 to 80 per cent
Power requirements 100 to 115 V AC, 60 Hz (domestic); 220 to 240 V AC, 50 Hz (international)

[1]

The Celsius figure in Apple's table does not match the Fahrenheit one: 90.5 °F is 32.5 °C, the figure Apple's pre-power-on checklist uses.[1]

Safety

[edit | edit source]

Apple's warnings for the LaserWriter family:[1]

  • The printers operate at high voltages. Switch off and unplug the power cord before servicing, and never work on a LaserWriter under power except when making live adjustments. With the covers off and the power on, do not touch the high-voltage power supply or the DC power supply.
  • Never disconnect the optical fibre cable or open the laser access hatch with the printer switched on. The beam is infrared: it cannot be seen and can permanently damage the eyes. When servicing or adjusting the optical system, keep screwdrivers and other shiny objects out of the beam, whose reflection is just as dangerous. Warning labels are fitted inside the covers where exposure is possible.
  • The fuser rollers become very hot. Switch the printer off for at least five minutes before servicing the fuser assembly.
  • Do not be grounded when working on plugged-in equipment or making live adjustments, and remove all jewellery before starting.
  • The I/O boards contain CMOS parts that are very sensitive to static and skin acid. Handle chips, ROMs and SIMMs by their edges, do not touch anyone working on integrated circuits, and keep polyester clothing, plastic, vinyl and polystyrene out of the work area.
  • Apple's safety section gives LaserWriter printers as weighing from 32 to 60 pounds; its specification table gives this model as 77 lb. Take care when lifting.
  • Toner is a non-toxic mixture of plastic, iron and a little pigment. Remove it from skin and clothing with a dry tissue and wash with cold water; hot water makes it gel and fuse into fabric. Toner attacks vinyl.

Apple's guide also cautions against ammonia-based cleaners on the LaserWriter II and Personal LaserWriter, because they discolour the plastic, and its LaserWriter checklist asks whether the printer is exposed to ammonia gas.[1]

Status lights

[edit | edit source]

The LaserWriter has three status lights on the front display panel and a Test light on the rear I/O connector plate.[1]

LaserWriter status lights
Light Position Behaviour
Ready/Wait (green) Front panel Flashes during warm-up; on continuously when ready to print
Paper-Out (yellow) Front panel On and steady when out of paper or when the cassette is not installed; flashes while the printer prepares to print a page. In manual feed mode, on steadily if there is no paper on the manual feed tray
Paper Jam (red) Front panel On when paper jams inside the printer, until the jam is cleared
Test Rear I/O connector plate On, steady or flashing, if there is an error condition on the I/O board. With a working I/O board it flashes once at switch-on and then goes out

[1]

Test prints

[edit | edit source]

The two test prints check different halves of the printer.[1]

The service test print checks the print engine alone. Produce it by jumpering pins J205-1 and J205-2 on the DC controller PCB; it separates print-engine faults from I/O board faults.[1]

The user test print is produced each time the printer is switched on, unless the protocol switch is set to "Special" or the print has been turned off with PostScript software. It confirms that the I/O board works and shows the revision of the PostScript ROMs, the selected mode (PostScript or Diablo 630 emulation) and the number of pages the I/O board has produced.[1]

A fault that appears on the service test print is in the engine. A fault that appears only on the user test print, or only when printing from a computer, is in the I/O board or beyond it.[1]

Ports and switches

[edit | edit source]

The rear panel has a 9-pin connector, a 25-pin connector and a four-position mode switch marked AppleTalk, Special, 9600 and 1200.[1]

AppleTalk connector, DB-9
Pin Signal Description
3 SG Signal ground
4 TXD+ Transmit data +
5 TXD− Transmit data −
8 RXD+ Receive data +
9 RXD− Receive data −

[1]

Setting the mode switch to AppleTalk selects this port.[1]

RS-232 connector, DB-25
Pin Signal Description
2 TD Transmit data
3 RD Receive data
4 RTS Request to send
7 SG Signal ground
20 DTR Data terminal ready

[1]

Setting the switch to 1200 or 9600 selects the RS-232 port at that rate. The AppleTalk cable is Apple's LocalTalk Connector Kit, DB-9, part number 590-0254 or 630-8272, model M2065.[1]

Troubleshooting

[edit | edit source]

Pre-power-on checklist

[edit | edit source]

Apple's checklist before chasing a fault:[1]

  • Line voltage 115 V AC ±10%
  • Printer on a solid, level surface
  • Room temperature 50-90 °F (10-32.5 °C) and humidity 20% to 80%
  • Printer not in an excessively hot, humid or dusty place or near open flames
  • Printer not exposed to ammonia gas (produced by diazo copiers or cleaning solutions)
  • Printer out of direct sunlight and in a well-ventilated area
  • Cables and connectors OK
  • Toner cartridge installed and OK; replace it if the indicator is red
  • Fuser roller cleaner felt in place and not dirty
  • Print density dial set correctly
  • Protocol selector switch on the back set to AppleTalk
  • Paper cassette loaded to no more than 10 mm high
  • Paper 16-21 lb standard photocopier paper
  • Transfer corona wire clean and unbroken
  • Separation belt free of nicks and not broken

Diagnostic sequence

[edit | edit source]

Apple's order is the pre-power-on checklist, then the LaserWriter Functional Check, then the LaserWriter Print Engine Check, then the lettered troubleshooting tables.[1] The functional check starts by switching the printer off, waiting one minute, switching it on and waiting three minutes for a user test print; if that is good, it sends a file from a Macintosh over AppleTalk.[1]

The tables cover: A, no power; B, delivery rollers do not rotate; D, heater bulb does not operate; E, cannot feed paper manually; F, jams detected when there are none; G, paper jams not detected; H, Paper-Out light on when there is paper; J, preconditioning lamps do not light; K, laser/scanner malfunction; L, erroneous low-toner indication; M, print quality problems; N, paper transport problems.[1]

Adjustments

[edit | edit source]

Laser power adjustment

[edit | edit source]

This needs a laser power checker and a digital multimeter.[1]

  1. Remove the top cover, the I/O board and the card cage.
  2. With the power off, open the laser access hatch and insert the laser power checker with the detector facing the laser diode. Insert it fully so that no laser light can escape from the hatch.
  3. Connect the checker's black lead to the meter's common socket and the red lead to volts, and set the meter to the 200 mV range.
  4. Disconnect J209 from the DC controller board and jumper J209-5 to J209-6.
  5. Turn VR202 on the DC controller board fully anticlockwise.
  6. Switch on and wait until the green Ready/Wait light stops flashing.
  7. Briefly jumper J209-6 to J209-7, remove the jumper and record the reading. Repeat twice more.
  8. Average the three readings and compare the result with the voltage printed next to "300" on the laser label; it should be within ±1 mV.

If the output is low, remove the J209-6/J209-7 jumper, turn VR202 slightly clockwise and repeat; if it is high, turn VR202 slightly anticlockwise and repeat.[1]

Image skew adjustment

[edit | edit source]

To check the skew, produce a user test print and measure from the top left and right corners of the test pattern to the top edge of the paper. The two measurements should differ by no more than 1 mm.[1]

To adjust it:[1]

  1. Remove the top cover and the I/O board. Switch on and wait for the green Ready/Wait light to stop flashing.
  2. Produce a service test print by briefly jumpering J205-1 to J205-2.
  3. Loosen the four large mounting screws on the scanner unit and the two sealed screws closest to the laser unit.
  4. Rotate the scanner unit around screw A. Clockwise inclines the horizontal line anticlockwise; anticlockwise inclines it clockwise.
  5. Reprint and remeasure until the difference is 1 mm or less.
  6. If you run out of travel, tighten the two sealed screws nearest the laser unit, loosen the two on the other side and rotate around screw B.

Preventive maintenance

[edit | edit source]

Reading the page count

[edit | edit source]

The user test print gives the number of pages printed since the I/O board was installed, which is the machine's page count only if that board has never been replaced or upgraded.[1] Otherwise, remove the top cover, the I/O board and the DC controller board, and find the page counter in the middle of the preconditioning exposure assembly, just below the DC controller board. It looks like a small thermometer, and each mark represents about 10,000 pages.[1]

Apple's schedule

[edit | edit source]
Preventive maintenance schedule
Pages Procedure
0 to 50,000 Standard Maintenance
50,000 to 100,000 Standard Maintenance, and replace the ozone filter
100,000 to 150,000 100,000-Page Service, and replace the separation belt

[1]

Standard Maintenance: open and close the toner cartridge's light-blocking shutters to check they are not jammed or broken; clean the cartridge's primary corona wire with the wire brush supplied with the printer; clean the protective shield with a damp cloth; clean the photosensitive drum only if absolutely necessary, with a soft cloth saturated with toner powder; replace the fuser roller cleaner felt if it is dirty; clean the separation claws, delivery guide, separation guide and paper guide with isopropyl alcohol; clean the transfer corona assembly and separation belt with a cotton swab; clean the feeder rollers, separation rollers, transfer guides and feeder guide with isopropyl alcohol; and replace the ozone filter every 50,000 pages.[1]

The 100,000-Page Service adds cleaning the fan with a small brush and the registration shutter rollers with isopropyl alcohol, and replacing the preconditioning exposure assembly, the grounding spring, the paper pickup rollers, the paper feed rollers and lower paper feed guide, the fuser assembly, the ozone filter and the separation belt.[1]

Before starting, switch off and unplug the printer, let the fuser rollers cool, take ESD precautions and lay a drop cloth to protect the floor from grease and toner.[1]

Parts

[edit | edit source]

Selected entries from Apple's parts list:[1]

Part Number
DC controller PCB 661-0267
DC power supply/motor drive PCB, 110 V 661-0273
DC power supply/motor drive PCB, 220 V 661-0274
High-voltage power supply 661-0266
Laser unit 661-0277
Scanner unit, 300 dpi 661-0278
LaserWriter I/O PCB 661-0436
Fuser assembly, 115 V 661-0450
Fuser assembly, 220 V 699-0318
Power interlock assembly, 110 V 699-0324
Power interlock assembly, 220 V 699-0325
AC driver PCB, 110 V 661-0268
AC driver PCB, 220 V 661-0269
Paper separator belt 970-1005
Ozone filter 970-1001
Transfer corona assembly 970-1021
Fan, 110 V 60 Hz 720-0502
Fan, 220 V 50 Hz 970-1074
Main drive motor 970-1009
Preconditioner exposure PCB 970-1020
Registration shutter assembly 699-0323
Separation/feed roller assembly 970-1019
Display panel assembly 970-1109
LaserWriter configuration block 750-0102

The DC power supply, AC driver PCB, power interlock, fuser assembly and fan all have different part numbers for 110 V and 220 V machines.[1]

Service manual

[edit | edit source]

Other documentation on this wiki

[edit | edit source]
  • Service Support Tranning Programs Laserwriter Technical Procedures Jan 1985: Apple's LaserWriter Printer Technical Procedures, the earliest service document for this printer held here, marked on its contents page as "a preliminary version ... for internal use only", with sections stamped rev. Jan 85 and rev. Feb 85. It gives the two adjustments above under their Apple procedure numbers (Laser Power Adjustment, P/N 011-7052; Image Skew Adjustment, P/N 011-7051), a theory of operation (300 dpi, 6.8 million dots per page; the I/O board is a 68000 with 1.5 MB of RAM and 500 KB of ROM), a full take-apart including the fuser assembly, part 699-0306, image-defect and electromechanical troubleshooting tables, and an appendix of DC controller board signals and connectors.[2] The same binder also contains Apple's Macintosh Office (AppleTalk), DuoDisk and UniDisk technical procedures, ImageWriter and Scribe parts lists, and extracts from the Lisa troubleshooting guide.[2]
  • Envelope Feeder Service Source: Apple's service manual for the LaserWriter envelope feeder. The Pro 600/630 feeder fits only that printer; the 16/600 PS feeder fits both. The manual gives three ways to tell them apart (two-piece or one-piece roller shafts, controller board RG5-0576 or RG1-3437, serial prefix JXC or LBK) and the 1.5 mm separation-guide gap to reset after a strip-down.
  • Service Training Introduction To Laser Printer Service Version 1.0.1 1996: Apple's technician course on the diagnostic method for laser printers. The 1992 edition includes the final test.
  • The Laser Writer Family 1992: Michael Fraase's Rapid Reference Guide to The LaserWriter Family (Business One Irwin, 1992), a third-party user guide to the Personal LaserWriter LS and NT and the LaserWriter IIf and IIg, with no schematics, parts list or FRU numbers.
  • Inside The Apple Laserwriter 1989: Roger Hart, Scott, Foresman and Company, 1989, 313 pages. A third-party book on using and programming the LaserWriter (PostScript, fonts, page description), with no service procedures, parts or schematics.
  • Apple Laserwriter Reference 0-201-19258-6 1988: Apple's reference for the LaserWriter, LaserWriter Plus, II NT and II NTX, including the printer switch settings and font behaviour.
[edit | edit source]

References

[edit | edit source]
  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.30 1.31 Apple Service Guide for LaserWriter Printers, Volume I, Apple Computer, Inc., January 1992 (072-0631-B), hosted on this wiki as Apple LaserWriter Printers Volume I (PDF). Covers the LaserWriter, LaserWriter Plus, LaserWriter II SC/NT/NTX/IIf/IIg and Personal LaserWriter SC/NT/LS. Introductory safety section: the high-voltage, optical-fibre, fuser-cooling, ESD, not-being-grounded and lifting warnings; the LaserWriter Safety Rules; the toner-safety paragraph; the laser-safety paragraph and the three laser warning labels. Tab 2, LaserWriter/LaserWriter Plus: parts list with part numbers (pages 3-4); print engine specifications (page 7); status lights (page 8); service test print and user test print (page 9); the pre-power-on checklist and troubleshooting flowcharts and tables (pages 10-51); the LaserWriter Plus ROM upgrade (pages 52-53); the laser power adjustment (page 54); the image skew adjustment (pages 55-56); and preventive maintenance including the page counter, the maintenance schedule and the Standard Maintenance and 100,000-Page Service checkpoint tables (pages 57-60). Tab 3, LaserWriter II: parts list (pages 4-5); controller-I/O board specifications (page 10); print engine specifications (page 11); status LEDs (page 12); test pages (page 13); the pre-power-on checklist, the IIf/IIg status-LED diagnostic chart and the troubleshooting tables (pages 14-54); the laser power output check (page 55); the NTX memory and ROM upgrades (pages 56-57); the IIf/IIg memory upgrade (page 58); and preventive maintenance (pages 59-60). Tab 6, Ports and Cables: the peripheral cable table, external connector diagrams, connector pin-outs and switch configurations.
  2. ↑ 2.0 2.1 Apple Computer, Apple LaserWriter Printer Technical Procedures, preliminary version for internal use only, sections stamped rev. Jan 85 and rev. Feb 85. Held on this wiki inside the Service Support Training Programs binder scan, described at Service Support Tranning Programs Laserwriter Technical Procedures Jan 1985 (File:Service_Support_Tranning_Programs_Laserwriter_Technical_Procedures_Jan_1985.pdf).


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