Apple LaserWriter II NT
| Apple LaserWriter II NT | |
|---|---|
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|
| Apple LaserWriter II (the NT, SC and NTX share this case) | |
| Manufacturer | Apple Computer, Inc. |
| Type | Laser printer |
| Interface | LocalTalk / RS-422 (mini DIN-8); RS-232 (DB-25); Apple Desktop Bus connector present |
| Compatible | Macintosh; other computers over RS-232 |
| Dimensions | 8.6 in high × 20 in wide × 18.5 in deep |
| Weight | 45 lb (20.25 kg) |
| Power | 90-126 V AC, 50-60 Hz |
| Part number | 661-0438 (NT controller-I/O board) |
The Apple LaserWriter II NT is the PostScript member of the LaserWriter II range. It shares the Canon LBP-SX engine, the case, the power supply and the mechanical parts with the II SC and the NTX. Its controller-I/O board has a 68000 at 11.16 MHz, 1.0 MB of ROM and 2.0 MB of RAM, and runs PostScript and Diablo 630 emulation over LocalTalk, RS-232 and RS-422.[1] Read the Safety section before taking the covers off: the printer contains an invisible laser, a fuser that needs five minutes to cool, and a high-voltage supply for the coronas.
Controller-I/O board
[edit | edit source]| SC | NT | NTX | IIf | IIg | |
|---|---|---|---|---|---|
| CPU | 68000 (7.45 MHz) | 68000 (11.16 MHz) | 68020 (16.67 MHz) | 68030 (20.0 MHz) | 68030 (25.0 MHz) |
| ROM | 16 KB | 1.0 MB | 1.0 MB | 2.0 MB | 2.0 MB |
| RAM | 1.0 MB | 2.0 MB | 2.0 MB, expandable to 12 MB | 2.0 MB, expandable to 32 MB | 5.0 MB, expandable to 32 MB |
| I/O | SCSI | LocalTalk, RS-232, RS-422 | LocalTalk, RS-232, RS-422, SCSI | LocalTalk, RS-232, RS-422, SCSI | LocalTalk, RS-232, RS-422, SCSI, Ethernet |
| Imaging languages | QuickDraw | PostScript, Diablo 630 | PostScript, Diablo 630, HP LaserJet | PostScript Level 1 and 2, HP LaserJet IIP | PostScript Level 1 and 2, HP LaserJet IIP |
| Built-in fonts | Times, Helvetica, Courier, Symbol | Times, Courier, Symbol, Palatino, Helvetica, Helvetica Narrow, ITC Bookman, ITC Avant Garde, ITC Zapf Chancery, New Century Schoolbook, ITC Zapf Dingbats | As NT | As NT | As NT |
Apple's guide gives memory upgrade procedures for the NTX and the IIf/IIg, and none for the NT, whose 2.0 MB is fixed.[1]
Board layout
[edit | edit source]Apple's service course diagram of the NT controller-I/O board shows an MC68000, a 6532, an 8530 SCC, 1 MB of ROM, 2 MB of RAM and SRAMs, with the Apple Desktop Bus connector, a two-position switch, the RS-232 port and the LocalTalk/RS-422 port along the back panel. The board connects to the print engine through a 32-pin right-angle connector that engages as the board slides into its guide rails.[2]
Board and ROM part numbers
[edit | edit source]| Part | Number |
|---|---|
| Controller-I/O board, LW II NT | 661-0438 |
| IC, ROM, L0 | 342-0545 |
| IC, ROM, H0 | 342-0546 |
| IC, ROM, L1 | 342-0547 |
| IC, ROM, H1 | 342-0548 |
| IC, ROM, L2 | 342-0549 |
| IC, ROM, H2 | 342-0550 |
| IC, ROM, L3 | 342-0551 |
| IC, ROM, H3 | 342-0552 |
The NT board carries eight ROMs in high and low pairs, L0/H0 to L3/H3. The NTX takes eight differently numbered ROMs (342-0560 to 342-0567, or 342-0711 to 342-0718 on the rev. 3 board), and the IIf and IIg take four (076-0860 to 076-0863).[1]
Ports and switches
[edit | edit source]The rear panel carries, left to right, an Apple Desktop Bus connector, the switches, the RS-232 port and the LocalTalk/RS-422 port. The SC, NT and NTX have the ADB connector; the IIf and IIg do not, and use a pushbutton switch instead. Apple's guide shows the connector but describes no function for it.[1]
| Pin | Signal | Description |
|---|---|---|
| 1 | HSKo | Handshake out |
| 2 | HSKi | Handshake in |
| 3 | TxD− | Transmit data − |
| 4 | SG | Signal ground |
| 5 | RxD− | Receive data − |
| 6 | TxD+ | Transmit data + |
| 7 | GPi | General-purpose input |
| 8 | RxD+ | Receive data + |
| Pin | Signal | Description |
|---|---|---|
| 1 | SGND | Signal ground |
| 2 | TxD | Transmitted data |
| 3 | RxD | Received data |
| 4 | RTS | Request to send |
| 5 | CTS | Clear to send |
| 6 | DSR | Data set ready |
| 7 | SG | Signal ground |
| 8 | DCD | Data carrier detect |
| 20 | DTR | Data terminal ready |
| 22 | RI | Ring indicator |
Switch configurations
[edit | edit source]The NT has two switches:[1]
| Communication and command mode | 1 | 2 |
|---|---|---|
| LocalTalk | Up | Up |
| Diablo 630 emulation | Down | Up |
| 9600 baud RS-232 and RS-422 | Up | Down |
| 1200 baud RS-232 and RS-422 | Down | Down |
The NTX has a six-switch bank with separate command-mode and handshaking groups, including a PostScript interactive mode and an HP LaserJet mode.[1]
Apple's cable for the NT is the LocalTalk Connector Kit, DIN-8, service part 590-0338 or 630-8275, model M2068, the same kit as for the NTX, IIf, IIg and Personal LaserWriter NT.[1]
Print engine
[edit | edit source]| Marking engine | Canon LBP-SX laser xerographic |
| Print resolution | 300 dots per inch |
| Speed | 8 pages per minute |
| Print materials | Letter, legal, A4 and B5 in 16-20 lb single-sheet photocopy bond, 8-34 lb letterhead and coloured stock, or overhead transparency film. Envelopes, labels and paper up to 36 lb by manual feed; envelopes also from an optional envelope tray |
| Print capacities | Paper cassettes hold 200 sheets of 20 lb paper; the envelope cassette holds 15 envelopes |
| Printable surface | Letter 8.0 × 10.5 in; Legal 8.0 × 13.0 in; A4 7.41 × 10.86 in; B5 7.69 × 10.16 in |
| Physical dimensions | Height 8.6 in (21.8 cm); width 20 in (50.8 cm); depth 18.5 in (47 cm); weight 45 lb (20.25 kg) |
| Operating environment | 50 to 90 °F (10 to 32.5 °C); humidity 20% to 80% |
| Power requirements | 90 to 126 V AC; 50 to 60 Hz |
The four subsystems
[edit | edit source]Apple's service course divides the engine into four subsystems:[2]
- Power distribution: the AC inlet and power switch, the AC driver board and fuser heater, the DC power supply/motor driver PCA, the high-voltage power supply for the primary corona, transfer corona and developing bias, and the distribution PCA.
- Control: the DC controller PCB, which receives the print command from the controller-I/O board, controls the rest of the engine and reports status on the front-panel LEDs. The course tells technicians always to check the DC controller, because a module that seems faulty may not have received its command or its supply.
- Image formation: the laser diode, scanning motor and optical fibre, the photosensitive drum, the coronas, the static-charge eliminator, the toner sensor and the fuser.
- Pickup and feed: the cassette, the pickup and registration rollers, their solenoids and the paper sensors.
Sensors, switches and solenoids
[edit | edit source]| Designator | Location | Function |
|---|---|---|
| PS301 | Distribution PCA | Paper-out sensor; senses paper in the cassette |
| PS302 | Distribution PCA | Manual feed sensor; uses the same arm as PS301 |
| PS331 | Fuser PCA or fuser assembly PCA | Paper delivery sensor. If paper fails to reach and clear it in time, a jam is reported |
| SL301 | Distribution PCA | Pickup roller solenoid; engages the clutch that turns the pickup roller |
| SL302 | Distribution PCA | Registration roller clutch solenoid |
| SW301, SW302 | Distribution PCA | Drum-sensitivity switches, set by the toner cartridge |
| Interlock switch | Top of the DC power supply | Cuts power when the upper unit opens |
Because PS301 and PS302 share one arm, a bent or sticking arm can affect both the paper-out and the manual-feed indications.[2]
Safety
[edit | edit source]The LaserWriter family safety rules apply:[1]
- Switch off and disconnect the power cord before servicing. Parts are live under power; never work on the printer under power except when making live adjustments. With the covers off and the power on, do not touch the high-voltage power supply, the DC power supply or the power supply block.
- Do not disconnect the optical fibre cable with the printer on. It carries the infrared laser beam, which cannot be seen and can permanently damage the eyes. Keep screwdrivers and other shiny objects out of the beam path; the reflection is equally dangerous. The warning labels inside the covers read "DANGER - INVISIBLE LASER RADIATION WHEN OPEN. AVOID DIRECT EXPOSURE TO BEAM."
- The fuser rollers become very hot. Switch off for at least five minutes before servicing them.
- Do not be grounded when working on plugged-in equipment or making live adjustments, and remove all jewellery first.
- The controller-I/O board contains CMOS parts; handle chips, ROMs and SIMMs by their edges.
- The printer weighs 45 lb.
- Toner is non-toxic (plastic, iron and a little pigment). Remove it with a dry tissue and wash with cold water; hot water makes it gel and fuse into fabric. Toner attacks vinyl.
- Never use an ammonia-based cleaner on the LaserWriter II; it discolours the plastic.
Status LEDs
[edit | edit source]The LaserWriter II has four status LEDs, all on the front panel.[1][2]
| LED | Colour | Behaviour |
|---|---|---|
| Ready | Green | Flashes during warm-up and while printing; steady when ready; off when the printer is not ready, an error exists or the top cover is open |
| Low-Toner | Orange | Steady when the toner cartridge needs replacing; flashes when the cartridge is installed incorrectly |
| Paper-Out | Red | Steady when out of paper or the paper tray is missing; flashes when the printer is ready for a manually fed sheet |
| Paper Jam | Red | On when paper jams, until the jam is cleared |
When the Paper-Out and Paper Jam lights flash together, the controller-I/O board or the print engine has an error condition.[1]
Things that are not faults
[edit | edit source]- After a new toner cartridge is fitted, the NT's Low-Toner LED stays on until the printer produces a printout or is switched off and on again.[1]
- A flashing Low-Toner LED means the cartridge is seated wrongly.[1]
- A flashing Paper-Out LED means the printer is waiting for a hand-fed sheet.[1]
Test pages
[edit | edit source]The engine self-test page checks the print engine alone. Press the engine self-test switch on the side of the printer, behind the access cover; no computer or network is involved.[1]
The NT prints a startup test page every time it is switched on, unless this has been turned off with PostScript software or with the LaserWriter Utility on the LaserWriter II Installation disk. It confirms that the controller-I/O board works and shows the page count.[1]
A fault on the engine self-test page is in the engine. A printer that gives a clean self-test page but no startup page points to the controller-I/O board; one that passes both but will not print from a computer points to the cable, the switch settings, the driver or the host.[1]
Troubleshooting
[edit | edit source]Pre-power-on checklist
[edit | edit source]Apple's list, to work through before the flowcharts:[1]
- Line voltage 115 V AC ±10%
- Printer on a solid, level surface
- Room temperature 50-90 °F (10-32.5 °C), humidity 20% to 80%
- Not in a hot, humid or dusty place or near open flames
- Printer not exposed to ammonia gas
- Out of direct sunlight and well ventilated
- Cables and connectors OK
- Toner cartridge installed and containing toner
- Fuser roller cleaner felt in place and not dirty
- Print density dial set correctly
- Paper cassette properly loaded and paper within specification
- Transfer corona wire clean and unbroken
- I/O PCA DIP switches set correctly
Troubleshooting order
[edit | edit source]Apple's sequence is: work through the pre-power-on list; read the safety section before any live electrical check; for an SC or NT/NTX, start with Troubleshooting Flowchart 1 and continue function by function until every main function is verified; if a replacement module does not cure the fault, refit the original before going on; and carry out preventive maintenance before returning the printer.[1] The status-LED diagnostic with the rotary switch and the LaserWriter II Test Connector applies only to the IIf and IIg.[1]
Laser power output check
[edit | edit source]This needs a laser power checker and a digital multimeter. The correct reading is 17.6 mV ±1.6 mV.[1]
- Put the printer on a grounded workbench pad and remove the controller-I/O board and the cover set.
- With the power off, open the laser access hatch on the laser/scanner assembly.
- Insert the laser power checker with the detector facing the laser diode.
- Connect the black lead to the meter's common socket and the red lead to volts; set the meter to the 200 mV range.
- Defeat the top cover interlock switch with a nonmetallic tool, switch on and wait one minute for warm-up.
- Depress drum-sensitivity switches SW301 and SW302, below the top cover interlock switch, and press the service test print button.
- Read the meter: 17.6 mV ±1.6 mV.
If no power can be measured, Apple's order is to replace the laser/scanner assembly and repeat, then the DC controller PCA.[1] The procedure runs the laser with the covers off and the interlock defeated.
Preventive maintenance
[edit | edit source]Before starting, switch off and unplug, let the fuser rollers cool, take ESD precautions and lay a drop cloth against grease and toner.[1]
Page count
[edit | edit source]The number at the bottom of the startup test page is the pages printed since the controller-I/O board was installed. If the board has been replaced or upgraded, Apple's instruction is to check the Repair Log Label on the bottom of the printer and ask the customer.[1]
Apple's parts replacement schedule
[edit | edit source]Every 50,000 prints, replace the ozone filter and check the fan. Every 100,000 prints, replace the fuser assembly, the transfer guide assembly, the preconditioning exposure assembly, the paper feed roller assembly and the transfer corona assembly.[1]
Cleaning
[edit | edit source]| Service point | Tool or solvent |
|---|---|
| Primary corona wire | Cleaning brush supplied with the printer |
| Transfer corona wire | Cotton swab (with isopropyl alcohol, for user cleaning) |
| Transfer guide | Cloth dampened with water |
| Fuser rollers | Fuser cleaning pad |
| Exterior case | Cloth dampened with water |
| Separation claws | Cloth dampened with alcohol |
| Paper guide | Cloth dampened with alcohol |
| Lower delivery guide | Cloth dampened with alcohol |
| Feeder guide | Cloth dampened with water |
| Registration rollers | Cloth dampened with water |
The customer cleans the first five items as needed; the dealer cleans all ten every 12 months or at each service call.[1]
Parts
[edit | edit source]Selected entries, common to the LaserWriter II range except where the NT is named:[1]
| Part | Number |
|---|---|
| Controller-I/O board, LW II NT | 661-0438 |
| DC controller PCA | 661-0426 |
| DC power supply, 110/115 V | 661-0424 |
| DC power supply, 220/240 V | 661-0442 |
| Fuse, 125 V 6.3 A | 941-0005 |
| Fuse, medium time lag 3.15 A, 250 V | 740-0061 |
| High-voltage power supply | 661-0425 |
| Laser/scanner assembly | 661-0423 |
| Fuser assembly, 110/115 V | 661-0440 |
| Fuser assembly, 220/240 V | 661-0444 |
| Fuser heater, 100 V, 620 W | 938-0003 |
| Fuser heater, 220 V, 570 W | 938-0004 |
| Fuser roller cleaner | 970-0049 |
| Ozone filter | 961-0003 |
| Ozone filter (for case with door) | 961-0007 |
| Power supply block, 110/115 V | 661-0427 |
| Power supply block, 220/240 V | 661-0443 |
| Distribution PCA | 971-0028 |
| Transfer corona assembly | 971-0026 |
| Transfer guide assembly | 971-0019 |
| Paper feed roller assembly | 971-0017 |
| Feeder assembly | 971-0018 |
| Delivery assembly | 971-0023 |
| Main motor assembly | 971-0014 |
| Fan, lower | 959-0021 |
| Fan, upper | 959-0022 |
| Status panel | 971-0005 |
| Cleaning brush | 970-0047 |
| Mirror assembly | 971-0007 |
The DC power supply, fuser assembly, fuser heater and power supply block are different parts for 110 V and 220 V machines, and the two fuser heaters are rated 620 W at 100 V and 570 W at 220 V.[1]
Service manuals
[edit | edit source]
Related pages
[edit | edit source]- Apple LaserWriter II SC
- Apple LaserWriter
- Apple LaserWriter Plus
- Apple Personal LaserWriter 300
- LaserWriter II Service Source
References
[edit | edit source]- ↑ 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 1.32 1.33 1.34 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 3, LaserWriter II: parts list including the NT controller-I/O board and its ROM set (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 troubleshooting flowcharts and tables including the NT low-toner note (pages 14-54); the laser power output check (page 55); and preventive maintenance including the page count, the parts replacement schedule and the user and standard maintenance tables (pages 59-60). Tab 6, Ports and Cables: the peripheral cable table, external connector diagrams, the RS-422 and RS-232 pin-outs and the LaserWriter II NT switch configuration table.
- ↑ 2.0 2.1 2.2 2.3 2.4 Apple Service Training: LaserWriter II Service Course, Participant Manual, Version 1.1, Apple Computer, Inc., October 1992, hosted on this wiki as LaserWriter II Service Course: Participant Manual (PDF). Module 1, "LaserWriter II Parts and Functions": the SC, NT and NTX I/O board block diagrams and back panels (figures 1-3 to 1-5) and the 32-pin right-angle engine connector; the four-subsystem breakdown (power distribution, control, image formation, pickup/feed); the power distribution diagram (figure 1-7); the DC controller PCB's role; the interlock switch at the top of the DC power supply; the status panel description; the distribution PCA (figure 1-12) with drum-sensitivity switches SW301 and SW302, pickup solenoid SL301, registration clutch solenoid SL302, paper-out sensor PS301 and manual feed sensor PS302; and paper delivery sensor PS331 on the fuser PCA.