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This guide documents preventive maintenance procedures for the '''[[IBM PS/2 Model 30]]''' (machine type 8530), covering both the original Model 30 8086 (8530-002 / 021) and the later Model 30 286 (8530-E01 / E21 / E31 / E41). The Model 30 is a desktop-form-factor PS/2 with no integrated CRT (unlike the [[IBM PS/2 Model 25|Model 25]]), so the system unit can be opened and serviced at the bench with low electrical risk to the technician.
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[[File:IBM PS2 Model 30 286 front view.jpg|thumb|300px|An IBM PS/2 Model 30 286 (8530-E series). The 286 machines are the ones with a voltage selector switch on the rear and a Dallas RTC module on the planar. (Image: DigitalIceAge, CC BY 4.0, via Wikimedia Commons)]]
This guide documents preventive maintenance on the '''[[IBM PS/2 Model 30]]''' (machine type 8530), covering both the original Model 30 8086 (8530-002 and 8530-021) and the later Model 30 286 (8530-E01, E21, E31, E41). The Model 30 is a desktop-form-factor PS/2 with no integrated CRT, unlike the [[IBM PS/2 Model 25|Model 25]], so the system unit can be opened and worked on at the bench with far less electrical risk.


== Safety Warning ==
== Safety Warning ==


The Model 30 PSU rectifies mains directly and holds a charge on its bulk capacitor for tens of seconds after power-off. Before any work inside the PSU shell:
The power supply rectifies the mains directly and its bulk capacitor holds that charge after the lead is pulled &mdash; roughly 170 V on a 120 V mains, roughly 325 V on a 230 V mains. Before any work inside the supply's shell:


# Power off and unplug the mains lead.
# Power off and unplug the mains lead.
# Wait at least 30 seconds.
# Bleed the bulk capacitor through a resistor across its terminals (1&nbsp;kΩ / 5&nbsp;W is the usual workshop choice).
# Discharge the bulk capacitor through a 1 kΩ / 5 W resistor between its two terminals.
# Confirm on a DC range that it is down to a few volts.
# Verify with a multimeter.


There is no CRT inside the Model 30 itself, so the lethal CRT-anode procedure from the [[IBM PS/2 Model 25 Maintenance Guide]] is not needed unless servicing the matching IBM 8503 / 8512 / 8513 / 8514 PS/2 monitor.
If your machine is a Model 30 286, '''check the voltage selector switch on the rear before plugging the cord in'''. It must be set to the 100&ndash;125 Vac or the 200&ndash;240 Vac range to match your supply.<ref name="atpower">Louis Ohland, Tomáš Slavotínek ''et al.'', "8525 / 8530 Power", Ardent Tool of Capitalism, https://www.ardent-tool.com/8530/Power.html. Transcribes IBM's Hardware Maintenance Service data for the 8525 and 8530: the P3/P4 and J7 connector measurement limits, the minimum under-voltage sense levels, the power-good range and the dead-system isolation procedure, and the warning that the manually-switchable supply must be set before the cord is plugged in.</ref><ref name="ann189035">IBM Announcement Letter 189-035, ''Personal System/2 Model 30 286 (8530-E01)''. Gives the 90-watt dual-voltage power supply with a switch on the rear, the 90&ndash;137 Vac and 180&ndash;265 Vac input ranges, the 10 MHz 80286, VGA graphics and the 1.44 MB diskette drive.</ref> The 8086 Model 30's supply is the internal-sensing type and has no switch.<ref name="ann187048">IBM Announcement Letter 187-048, ''IBM Personal System/2 Model 30 (8530-002, -021)'', 2 April 1987. Gives the "Universal 70W power supply, with internal sensing, for worldwide usage", and the 8530-002 (two 720 KB diskette drives) and 8530-021 (20 MB fixed disk with integrated controller plus one 720 KB diskette drive) configurations.</ref>
 
There is no CRT inside the Model 30 itself, so the anode-discharge procedure needed on the [[IBM PS/2 Model 25 Maintenance Guide|Model 25]] does not apply unless you are servicing the matching PS/2 display, in which case see [[CRT Discharge Procedure]].


== Identifying Your Model ==
== Identifying Your Model ==


The two Model 30 generations are distinguished by:
<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:100%; text-align:center;"
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Model 30 generation identification'''
|+'''Model 30 generation identification'''
! Marker !! Model 30 8086 !! Model 30 286
! Marker !! Model 30 8086 !! Model 30 286
|-
|-
| Front badge || "Personal System/2" with no "286" || "Personal System/2 / 286"
| Machine types || 8530-002, 8530-021 || 8530-E01, E21, E31, E41
|-
| CPU || Intel 8086-2 at 8 MHz, at planar U10 || Intel 80286 at 10 MHz, at planar ZM36 (PGA socket on early boards, PLCC on later)
|-
| Chipset || IBM gate arrays || VLSI VL82CPCAT-QC, at ZM2&ndash;ZM6
|-
|-
| CPU at planar U-position || Intel 8086 || Intel 80286 in PGA socket
| Video || MCGA || VGA
|-
|-
| ISA bus on riser || 8-bit only || 16-bit (longer connector)
| Riser || three 8-bit ISA slots || 16-bit ISA
|-
|-
| Aux power connector || absent || present (4-pin to ISA bus)
| Extra bus power connector || absent || present (J14, 4-pin, feeds the 16-bit bus)
|-
|-
| Hardware RTC || absent &mdash; date/time set every boot || present (Dallas DS1287 / DS12887)
| Real-time clock || NS MM58167AN at planar U16, battery on the riser card || Dallas DS1287 module at ZM35, cell sealed inside
|-
|-
| Video || MCGA &mdash; only on integrated DSUB || VGA &mdash; full 16-colour 640×480
| Diskette drive as shipped || 720 KB || 1.44 MB
|-
|-
| FDD type at install || 720 KB || 1.44 MB
| Power supply || 70 W, internal sensing, no voltage switch || 90 W, dual voltage, switch on the rear
|}
|}


Submodel and IBM machine type are printed on the rear panel label (e.g. "Type 8530-E21").
Sources for this table: the planar designator maps,<ref name="at8530planar">Louis Ohland, Tomáš Slavotínek ''et al.'', "8530 Planar (8086)", Ardent Tool of Capitalism, https://www.ardent-tool.com/8530/Planar.html. Gives the "P-PLANAR" P/N 61X8823 designator map, the two Greenock planar variants (P/N 33F4888 and FRU P/N 33F8474 / P/N 33F4871), the ROM image list, the riser card part numbers (61X8864, 61X8910) and its B1 3 V lithium battery (Panasonic BR-2/3A), the note that reference designators are largely consistent across all 8086-based Model 30 and Model 25 planars, and IBM retain tips H007157, H043664, H067282 and H094152.</ref><ref name="at8530planar286">Louis Ohland, Tomáš Slavotínek ''et al.'', "8530 286 Planar", Ardent Tool of Capitalism, https://www.ardent-tool.com/8530/Planar_286.html. Gives the full 8530-286 planar designator map (VL82CPCAT-QC chipset at ZM2&ndash;ZM6, VL16C451 at ZM9, DS1287 RTC/CMOS at ZM35, 8042/8742 keyboard controller at ZM33, 286-10 CPU at ZM36), the early PGA and later PLCC builds with FRU P/N 34F0046, the J13 password-override jumper and IBM retain tip H036143.</ref> IBM's announcement letters,<ref name="ann187048" /><ref name="ann189035" /> and IBM's ''Technical Reference''.<ref name="tr30">IBM, ''IBM Personal System/2 Model 30 Technical Reference'', January 1987. [[:File:IBM PS2 Model 30 Technical Reference Jan87.pdf]]. Section 1 lists the system board's integrated I/O functions, including "Real-time clock with battery", the I/O address map (real-time clock at hex 00B0&ndash;00BF and 00E0&ndash;00EF), and the diskette and fixed-disk connector pin assignments. Section 3 "Power Supply", pages 3-3 to 3-6, gives the 70 W rating, rail currents, regulation tolerances, under-voltage sense levels, power-good characteristics and the P3/P4 pin assignments.</ref>
 
The machine type and submodel are printed on the rear panel label, for example "Type 8530-E21".
 
== Planar Layout ==
 
The 8086 planar exists as the original "P-PLANAR" P/N 61X8823 and two later Greenock builds, P/N 33F4888 and FRU P/N 33F8474 (P/N 33F4871). The layouts look nothing like each other, but '''the reference designators are largely consistent across all of them''' &mdash; and across the 8086-based Model 25 planars too, which makes this map useful on either machine.<ref name="at8530planar" />
 
{| class="wikitable styled-table" style="width:100%;"
|+'''Model 30 8086 planar &mdash; principal designators'''
! Designator !! Device
|-
| J1 / J2 || Mouse / keyboard connectors (Mini-DIN-6, not interchangeable)
|-
| J3 || Parallel port (DB-25)
|-
| J4 || Video connector (HD-15)
|-
| J5 || Serial port (DB-25)
|-
| J6 || Riser slot
|-
| J7, J9 || Power connectors
|-
| J10 || 2-pin keylock header
|-
| J11 || 44-pin fixed-disk connector
|-
| J12 || 40-pin diskette connector
|-
| J13 || Dual 30-pin SIMM socket
|-
| F1 / F2 || Mouse and keyboard fuses (combined into F1 on the later alternative Greenock board)
|-
| U5 || Inmos IMSG171S RAMDAC
|-
| U8 || Intel P8253-5 timer
|-
| U10 || Intel 8086-2 CPU, 8 MHz
|-
| U13 || 8087 coprocessor socket
|-
| U16 || NS MM58167AN real-time clock
|-
| U17, U20 || ROM BIOS (even / odd)
|-
| U18 || NEC µPD765AC diskette controller
|-
| U19 || 8237A DMA controller
|-
| U27 || NS8250AV UART
|-
| SP1 || Piezo speaker
|-
| Y1 / Y2 / Y3 || 14.31818 MHz / 25.175 MHz / 48.000 MHz oscillators
|-
| Y4 || 32.768 kHz crystal (real-time clock)
|}
 
On the 286 planar the numbering changes to a ZM prefix: ZM2 VL82C100 peripheral controller, ZM3 VL82C102A memory controller, ZM4 VL82C103A address buffer, ZM5 VL82C104 data buffer, ZM6 VL82C101B system controller, ZM9 VL16C451 parallel/UART, ZM19 µPD765AC-2 diskette controller, ZM33 8042/8742 keyboard controller, ZM35 Dallas DS1287 RTC/CMOS, ZM36 the 286 CPU. Power arrives at J7 and J14, and J13 is the password-override jumper.<ref name="at8530planar286" />


== Opening the System Unit ==
== Opening the System Unit ==


Tools: Philips #2 screwdriver and an anti-static strap.
Tools: a Philips screwdriver, an anti-static strap and a plastic spudger.
 
# Turn off the system unit and every external option.
# Unplug the system unit's power cord from the outlet, then the cords of any external options.
# Remove all cables from the rear of the system unit.
# If the machine has a cover lock, unlock it and remove the key.
# Loosen the '''two cover screws''' and lift the cover off.<ref name="gto30286">IBM, ''Personal System/2 Model 30 286 Guide to Operations'', first edition, September 1988. [[IBM PS2 Model 30 286 Guide to Operations|IBM PS/2 Model 30 286 Guide to Operations]] ([[:File:IBM PS2 Model 30 286 Guide to Operations.pdf|PDF]]). "Cover Removal", page 2-2, and "Power-on Password Reset", pages 3-4 and 3-5, which locate the J13 jumper on the system board and describe moving it between the first-and-second and second-and-third pin positions.</ref>


# Power off and unplug all cables (mains, keyboard, mouse, monitor, parallel, serial).
[[File:IBM PS2 Model 30 286 open top.jpg|center|thumb|640px|A Model 30 286 with the cover off. The drive cage sits over the planar, the power supply alongside it, and the riser card at the rear. Drives and cards are held by plastic captive push-pin fittings, not screws. (Image: DigitalIceAge, CC BY 4.0, via Wikimedia Commons)]]
# Locate the two thumbscrews at the rear of the chassis (one each side, near the top).
# Loosen both thumbscrews; the cover slides back about 10 mm and lifts off upwards.
# The drive cage sits over the planar at the front-right. The PSU is at the front-left. The MCA / ISA riser card mounts to the rear-right corner.


Cards on the riser are held with plastic captive thumb-fittings. Drives are held with the IBM "blue plastic crowbar" push-pin system &mdash; pry the tabs gently with the plastic crowbar supplied with the machine, or with a thin plastic spudger. Do not use a metal screwdriver &mdash; the captive pins crack easily.
Inside, the drive cage sits over the planar and the supply is alongside it; the riser card mounts at the rear. Cards on the riser and the drives are held by IBM's plastic captive push-pin fittings. '''Lever these with a plastic spudger, never a metal screwdriver''' &mdash; the pins are brittle with age and snap, and a broken captive pin means the drive cage no longer locates properly.


== Regular Cleaning ==
== Regular Cleaning ==


* Soft brush + low-pressure compressed air for the planar, riser, drives and PSU vents. Hold any fan blades by hand if using compressed air.
* Soft brush and low-pressure compressed air for the planar, riser, drives and supply vents. Hold any fan blades still by hand while blowing, so the fan is not spun beyond its rated speed.
* Clean the keyboard / pointing-device Mini-DIN connectors with a deoxidising contact cleaner sparingly on a foam swab.
* Clean the Mini-DIN-6 keyboard and pointing-device connectors with a deoxidising contact cleaner on a foam swab, sparingly.
* Clean the parallel (DB-25) and serial (DB-9 or DB-25 depending on submodel) connectors.
* Clean the DB-25 parallel and serial connectors.
* Inspect the planar for any signs of leaked electrolyte (brown crust around aluminium electrolytic capacitors). The Model 30 is generally less prone to cap leakage than the Model 70 / 80, but inspect anyway.
* Inspect the planar for leaked electrolyte, and the diskette drive boards more carefully still &mdash; that is where PS/2 capacitor damage actually shows up. See [[IBM PS/2 Model 30 Capacitor Replacement Guide]].


== PSU Voltage Checks ==
== PSU Voltage Checks ==


Probe the PSU output rails at the planar power connector with a multimeter while the system is powered on.
Power reaches the planar through '''two 6-pin connectors, P3 and P4'''. P3 is the one nearer the rear of the system.<ref name="tr30" />


{| class="wikitable styled-table" style="width:100%; text-align:center;"
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Model 30 PSU rail tolerances'''
|+'''Model 30 power supply connector pin assignments'''
! Rail !! Acceptable range
! Pin !! P3 !! P4
|-
|-
| +5 V || +4.75 V to +5.25 V
| 1 || Power Good || Ground
|-
|-
| +12 V || +11.4 V to +12.6 V
| 2 || Ground || Ground
|-
|-
| &minus;5 V || &minus;4.75 V to &minus;5.25 V
| 3 || +12 V dc || &minus;5 V dc
|-
|-
| &minus;12 V || &minus;11.4 V to &minus;12.6 V
| 4 || &minus;12 V dc || +5 V dc
|-
| 5 || Ground || +5 V dc
|-
| 6 || Ground || +5 V dc
|}
 
Measure with the system powered on and running. IBM's service limits are given between specific pins, so put the meter's negative lead where the table says:
 
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Model 30 and Model 30 286 &mdash; service measurement limits'''
! Rail !! Negative lead !! Positive lead !! Minimum !! Maximum
|-
| +5 V || P3-5 || P4-4 || +4.8 V || +5.2 V
|-
| &minus;5 V || P4-3 || P3-6 || +4.6 V || +5.5 V
|-
| +12 V || P4-1 || P3-3 || +11.5 V || +12.6 V
|-
| &minus;12 V || P3-4 || P4-2 || +10.8 V || +13.2 V
|}
|}


The Model 30 PSU is rated '''70 W''' (early production) or '''80 W''' (later production, including some 8530-E units). The IBM Model 55 PSU is documented as a drop-in replacement.
The negative rails are measured with the leads reversed, which is why they read as positive numbers.<ref name="atpower" />
 
The supply shuts itself down if a rail falls below its under-voltage sense level: +4.5 V on the +5 V rail, &minus;4.3 V on &minus;5 V, +10.8 V on +12 V and &minus;10.2 V on &minus;12 V.<ref name="tr30" /><ref name="atpower" /> A rail sitting just above its trip point will run on the bench and then drop the machine as soon as it is loaded.
 
'''Power Good''' should read '''+3.5 V to +5 V''' at P3-1 when the system is operating correctly. If it does not, strip out all adapters, cables and extra memory and try again; if Power Good comes up, one of those devices was shorting a rail, and you find it by reinstalling them one at a time.<ref name="atpower" /> IBM specifies the line as TTL-compatible, active at 2.4 to 5.25 V dc, inactive at 0.0 to 0.4 V dc, with a turn-on delay of not less than 100 ms and not more than 500 ms.<ref name="tr30" />
 
The Model 30 286's supply adds the 4-pin bus power connector; other than that connector the two supplies are interchangeable in the chassis.<ref name="dosdays30">"IBM PS/2 Model 30", DOS Days, https://www.dosdays.co.uk/computers/IBM%20PS2%20Model%2030/ibm_ps2_model_30.php. Source for the single-cable drive interface with no Molex connectors, the extra 4-pin bus power connector on the Model 30 286, the statement that the fixed-disk interface is neither ESDI nor standard MFM, the drive caddy, and the Sony 1.44 MB drive compatibility note including the "1.44MB" marking on the eject button.</ref> '''Do not fit a Model 25 supply''': the Model 25 8086 does not use the same power connector as the Model 30 8086.<ref name="at8525planar">Louis Ohland, William R. Walsh, Tomáš Slavotínek ''et al.'', "8525 Planar", Ardent Tool of Capitalism, https://www.ardent-tool.com/8525/Planar.html. Gives the Model 25 planar designator maps, the warning that the Model 25 8086 does not use the same power connector as the Model 30 8086, the riser card contents, and William Walsh's account of the surface-mount electrolytic failures on PS/2 diskette drives and of undocumented 1.44 MB support with Sony drives.</ref>
 
== Real-Time Clock and Battery ==
 
'''Both generations have a hardware real-time clock.''' IBM lists "Real-time clock with battery" among the 8086 Model 30's integrated system-board functions, with the clock at I/O addresses hex 00B0&ndash;00BF (command/status) and hex 00E0&ndash;00EF (counter/RAM).<ref name="tr30" />
 
=== Model 30 8086 ===
 
The clock is a National Semiconductor '''MM58167AN at planar position U16''', timed by the '''Y4 32.768 kHz crystal'''.<ref name="at8530planar" />
 
The cell that backs it is '''not on the planar'''. It is a '''3 V lithium Panasonic BR-2/3A soldered to the riser card at B1''' &mdash; riser P/N 61X8864 or 61X8910, which also carries the three 8-bit ISA slots and, apart from the battery, nothing else of consequence.<ref name="at8530planar" /> If the clock on an 8086 Model 30 will not hold time, '''pull the riser, not the planar'''. This catches people out: the riser is the last place most restorers look for a battery.
 
IBM's own service notice on the subject is worth knowing about, because the early manual got it wrong. Retain tip '''H067282''' records that early releases of the 8530 Hardware Maintenance Service manual, on system board map page 0100-4, label the bus adapter card's pins incorrectly: the pins printed as "0" and "39" are actually pins 1 and 40, and the voltage should be measured at '''pins 38 and 39''' &mdash; the second and third pins in from the right-hand edge. Replace the bus adapter card if the voltage between the correct pins is below '''2.5 V'''.<ref name="at8530planar" />
 
=== Model 30 286 ===


== CMOS / RTC Battery (Model 30 286 only) ==
The clock is a '''Dallas DS1287 RTC/CMOS module at ZM35''', a 24-pin DIP with the lithium cell sealed inside it.<ref name="at8530planar286" /> When the cell runs down, POST reports:


The Model 30 8086 has '''no hardware RTC''' &mdash; date and time must be set manually from DOS at every boot. There is no battery to replace.
* '''161''' &mdash; battery. IBM's FRU order for this code is battery, then complex, then system board, then bus adapter.
* '''162''' &mdash; configuration changed; check that all devices are powered on and that the configuration has not been altered, then run Automatic Configuration. If that does not clear it, suspect the battery.
* '''163''' &mdash; date and time error; set the date and time.
* '''167''' &mdash; clock not running correctly.
* '''168''' &mdash; real-time clock error; run Advanced Diagnostics. This is not always a hardware failure.<ref name="aterr">"PS/2 Error Codes" and the error code listings, Ardent Tool of Capitalism, https://www.ardent-tool.com/trouble/ps2error.html. Error codes 160&ndash;199 (https://www.ardent-tool.com/trouble/error_02.html) and 300&ndash;999 (https://www.ardent-tool.com/trouble/error_04.html) give the 161/162/163/167/168 battery and clock cluster, the 301&ndash;307 keyboard cluster, 305 "keyboard voltage error" with the keyboard port fuse as the first FRU, and the 601&ndash;668 diskette cluster including 604 "unsupported drive or cable" and 662 "wrong drive type installed". The main page gives the dead-system isolation procedure.</ref>


The '''Model 30 286 uses a Dallas DS1287 / DS12887 RTC module''' integrated with the lithium cell. When the battery runs down, POST reports:
Replacement is by desoldering the 24-pin DS1287 and fitting a fresh DS12887+ or equivalent; some restorers instead cut into the original module's case to reach the cell and fit an external holder. IBM's own caution on the 161 code is worth repeating: '''the lithium cell presents a fire, explosion and burn risk''' &mdash; do not heat, crush, short or recharge it.<ref name="aterr" /> See [[Battery Refurbishment]] and [[Battery Explosion, Capacitor or Corrosion Damage]].


* '''161''' &mdash; CMOS configuration empty (battery failure).
After either job, boot the Reference or Starter Diskette and run Set Configuration to re-enter memory size, drive type and the date and time.
* '''162''' &mdash; CMOS checksum mismatch.
* '''163''' &mdash; Time and date not set.


Replacement is by desoldering the 24-pin DIP DS1287 / DS12887 from the planar and fitting a fresh '''Dallas DS12887+''' or a Dallas-cell-extracted equivalent. After replacement, boot the Reference Diskette and run SETUP to re-enter memory size, drive type and date/time.
=== Power-on password ===


Some restorers cut the DS1287's plastic case to expose the internal cell and add an external CR2032 holder; this works but is not as clean as a full module swap.
If the power-on password on a Model 30 286 is forgotten, move the '''J13''' jumper on the planar to its other position: if it covers the first and second pins, move it to the second and third, and vice versa. Leave it where you moved it until the next time it needs resetting.<ref name="gto30286" /><ref name="at8530planar286" />


== Connector Care ==
== Connector Care ==


* '''PS/2 keyboard / mouse (Mini-DIN-6)''': Plastic key in the connector aligns the plug; do not force.
* '''Keyboard and pointing device (Mini-DIN-6)''': these are two physically identical sockets with different functions &mdash; J1 is the mouse, J2 the keyboard.<ref name="at8530planar" /> They are not interchangeable. The plastic key aligns the plug; do not force it.
* '''Keyboard / pointing-device fuse''' on the planar (3 A) protects the +5 V to both ports. A blown fuse produces a 305 keyboard error at POST.
* '''Keyboard and mouse fuses''': F1 and F2 on the planar protect the +5 V feed to the two ports, combined into a single F1 on the later alternative Greenock board.<ref name="at8530planar" /> A '''305''' at POST is a keyboard voltage error, and IBM's first FRU for it is the keyboard port fuse.<ref name="aterr" />
* '''Parallel port (DB-25 female)''' and '''Serial port (DB-9)''' are standard.
* '''Parallel port''' (DB-25) and '''serial port''' (DB-25 on the 8086 planar) are conventional.<ref name="tr30" /><ref name="at8530planar" />
* '''Earphone connector (1/4" mono jack)''' at the rear routes the PC speaker through a passive divider for external amplification.


== Single-Cable Drive Interface ==
== Single-Cable Drive Interface ==


The Model 30 uses the PS/2 single-cable diskette and hard-drive interface. Power and data are carried in one ribbon cable from the planar to the drive. Care points:
The PS/2 drive interface carries power and data in one ribbon cable from the planar to the drive; there are no Molex connectors anywhere in the machine.<ref name="dosdays30" /> IBM's published pin assignments show exactly where the power sits:
 
* '''Diskette (J12, 40-pin)''': pin 38 is +5 V dc and pin 40 is +12 V dc; odd-numbered pins 1 to 35 are signal ground.<ref name="tr30" />
* '''Fixed disk (J11, 44-pin)''': pins 30 and 32 are +5 V dc, pins 40, 42 and 44 are +12 V dc.<ref name="tr30" />
 
Care points:
 
* Align the cable's stripe to pin 1 at both ends.
* Because the supply rails ride on the same connector as the data lines, a mis-inserted or offset cable puts +12 V onto signal pins. Check the alignment twice before powering up.
* The drives have no dust shutter, so dust reaches the heads. Clean periodically.<ref name="at8525planar" />
 
== Diskette Drive Maintenance ==
 
* The 8086 machines shipped with 720 KB drives and the 286 machines with 1.44 MB.<ref name="ann187048" /><ref name="ann189035" /> You can tell which you have from the blue eject button: a high-density drive has "1.44MB" moulded into it.<ref name="dosdays30" />
* Use DSDD media in a 720 KB drive. A '''662''' at POST means the wrong drive type is installed and a '''663''' means the wrong media type is in the drive; '''604''' means an unsupported drive or cable, the drive having to be a media-sense type.<ref name="aterr" />
* IBM never shipped the 8086 Model 30 with a high-density drive, but the machine does have undocumented 1.44 MB support. Sony-manufactured drives are the ones likely to work; other makes are recognised only as low-density, or not at all. Which planar you have also matters &mdash; the later boards are more tolerant.<ref name="at8525planar" /><ref name="dosdays30" />
* '''These drives have no belt.''' The Mitsubishi MF355C family rotates the disk with a DC brushless direct-drive motor coupled straight to the spindle at 300 rpm.<ref name="mf355c">Mitsubishi Electric, ''3.5 inch Flexible Disk Drive Standard Specifications, MF355C'', document UGD-0527A, February 1987. [[:File:Mitsubishi MF355C 3.5 inch Diskette Drive Specifications (UGD-0527A, Feb 1987).pdf]]. Section 3 states that the disk rotation mechanism uses a DC brushless direct-drive motor to rotate the spindle directly at 300 rpm.</ref> A drive that will not spin or spins slowly needs its board and motor examined, not a belt.
* The real wear item is the surface-mount electrolytics on the drive logic board, which leak and corrode the board underneath. See [[IBM PS/2 Model 30 Capacitor Replacement Guide]] and [[Floppy Drive Repair]].
 
== Fixed Disk Maintenance ==
 
The Model 30's fixed-disk interface is '''not ST-506, not ESDI and not IDE'''. IBM describes J11 as a dedicated I/O channel: it carries the ordinary I/O channel signals needed for fixed-disk operation &mdash; I/O read and write, reset, the data lines, I/O CH RDY, IRQ5 and the DMA request and acknowledge lines &mdash; plus a &minus;DISK CS card-select decoded at hex 032x, a &minus;DISK Installed line and address lines A0 to A2 to select a register inside the controller.<ref name="tr30" /> '''The controller is on the drive, not on the planar''': IBM's own announcement describes the 8530-021 as shipping with "one 20MB fixed disk with integrated controller".<ref name="ann187048" /><ref name="dosdays30" />
 
In practice:


* Pin 1 is marked with a red or blue stripe on the cable. Always align stripe-to-stripe.
* Only the original IBM drive assemblies are recognised, and the setup diskette offers no other drive types.<ref name="dosdays30" />
* Drive power is +5 V and +12 V routed through the planar; do not modify the cable to add Molex outputs.
* Those drives are failure-prone. If one will not spin up, suspect head stiction; rotating the drive body by hand with the power off sometimes frees it, but treat that as a way to get the data off, not as a repair.
* Drives have no dust shutter on the front bezel &mdash; dust accumulates and contaminates heads. Clean periodically with a head-cleaning diskette.
* Practical replacements are an XT-IDE card on the ISA bus, an SD-based emulator, or an MFM emulator &mdash; all of which sidestep the planar interface entirely.
* The drive sits in a metal caddy held by the same plastic captive push-pin mechanism as everything else.<ref name="dosdays30" />


== Floppy Drive Maintenance ==
IBM issued a service notice about drive and board combinations on these machines. Retain tip '''H007157''' records that successful fixed-disk operation on the 8530-001 and -021 depends on matching the system board, the drive and the version of Advanced Diagnostics used to format it &mdash; and that formatting with the wrong version of the diagnostics causes fixed-disk errors:<ref name="at8530planar" />


* The Model 30 ships with 720 KB or 1.44 MB drives depending on submodel.
{| class="wikitable styled-table" style="width:100%; text-align:center;"
* Use only the appropriate media type: DSDD for 720 KB drives, DSHD for 1.44 MB.
|+'''IBM retain tip H007157 &mdash; required FRU combinations'''
* Replace the drive belt if the drive is the Mitsubishi MF355C-family with a stretched/perished belt.
! Machine type !! System board !! Fixed disk !! Advanced Diagnostics
* Aluminium electrolytic capacitors on the drive logic board age and can leak; if the drive becomes slow or unreliable, recap the drive logic board with low-ESR 105 °C equivalents.
|-
| 8530-021 below serial 2500000 || P/N 61X8907 || P/N 61X8929 || 8530, any version
|-
| 8530-021 above serial 2500000 || P/N 33F8474 || P/N 6128285 || 8530, version 1.05
|-
| 8530-001, all || P/N 33F8474 || P/N 6128285 or 6128279 || 8530, version 1.05
|-
| 8530-E21 only || P/N 27F4069 || P/N 6128285 || 8530-286, version 1.02
|-
| 8530-E31 and E01 || P/N 34F0046 || P/N 6128285 or 6128279 || 8530-286, version 1.02
|}
 
Fixed disks P/N 6128285 and 6128279 must '''not''' be installed in any 8530-021 below serial number 2500000.<ref name="at8530planar" />


The drive logic board commonly carries 47 µF / 16 V and 10 µF / 25 V electrolytics. The brown crust of leaked electrolyte around these caps is a recognised PS/2 floppy-drive failure mode.
== Known IBM Service Notices ==


== Hard Drive Maintenance ==
Three more IBM notices are worth checking before chasing a fault on an 8530.


The Model 30 hard disk interface is '''proprietary planar-integrated ST-506''' &mdash; not ESDI, not standard MFM, and not IDE. Only a limited set of drives (specifically the two or three IBM-supplied parts in the original 8530-021 / E21 / E31 / E41 kits) are recognised.
* '''H043664 &mdash; cursor keys and 501 POST errors.''' On a limited number of 8530-001 and -021 machines, the cursor keys produce unexpected characters on the display, and a '''501''' appears when two or more option cards are fitted. Inspect the modules at planar positions '''U9''' (next to the coprocessor socket) and '''U15''' (next to the speaker). U9 P/N 72X8203 and U15 P/N 61X8965 are suspect if they are marked "IBM" but '''do not carry the word "Japan"'''; good parts have it. IBM's fix was to replace the system board with FRU P/N 64F3453. Machines with serial numbers above 55-00HV000 already have the new board.<ref name="at8530planar" />
* '''H094152 &mdash; 8515 and 8516 displays.''' The 8086 Model 30 (models 001, 002 and 021) does '''not''' support PS/2 8515 or 8516 displays; attaching one gives compressed, distorted video. It does support the 8503, 8504, 8507, 8512, 8513 and 8514. The 286 machines (E01, E21, E31, E41) support the 8503, 8504, 8512, 8513, 8514, 8515 and 8516.<ref name="at8530planar" />
* '''H036143 &mdash; 8602 with a 4717 printer.''' On a Model 30 286 shipped after 1 August 1989, attaching a 4717 directly gives an 8602 POST error and the printer does not work, because a planar change grounded pin 2 of the pointing-device port. IBM's fix was an interposer cable, P/N 31F6759.<ref name="at8530planar286" />


* These drives are famously failure-prone.
== Things That Are Not Faults ==
* If the drive does not spin up, suspect head stiction &mdash; gently rotate the drive case while powered off. This is a stop-gap; replace the drive at the earliest opportunity.
* Replacement options are limited because the BIOS only supports the original drive types in CMOS. An '''XT-IDE''' card on the ISA bus, an SD-based emulator, or a modern MFM emulator are practical replacements.


The hard drive sits in a metal caddy held to the chassis by the IBM plastic-captive push-pin mechanism.
* An 8086 Model 30 will not drive an 8515 or 8516 display properly. That is a documented limitation, not a fault.<ref name="at8530planar" />
* A '''162''' after you have added or removed a device is the machine noticing the change. Run Set Configuration before suspecting the battery.<ref name="aterr" />
* Soft-booting the Reference Diskette with Ctrl-Alt-Del can throw false errors and a false indication that a power-on password is already set. Cold boot with the diskette in the drive.<ref name="aterr" />
* A '''663''' means the diskette in the drive is the wrong media type for that drive. It is information, not a failure.<ref name="aterr" />


== Capacitor Health ==
== Capacitor Health ==


Tantalum capacitors on the planar (mostly 10 µF / 16 V on the +5 V and +12 V rails) can fail short-circuit and prevent the PSU from starting. The Model 30 is generally less affected than the Model 70 / 80 by aged electrolytics, but inspect the planar for any leaked electrolyte or bulged caps. Full procedure: [[IBM PS/2 Model 30 Capacitor Replacement Guide]].
Tantalum beads on the planar can fail short and stop the supply from coming up; aluminium electrolytics on the diskette drive boards leak and corrode. Full procedures, including what is and is not documented about this machine's capacitors, are in [[IBM PS/2 Model 30 Capacitor Replacement Guide]].


== Recommended Tools ==
== Recommended Tools ==


* Philips #2 screwdriver.
* Philips screwdriver and an anti-static strap.
* Anti-static strap.
* Plastic spudger for the captive push-pin fittings.
* Digital multimeter.
* Digital multimeter.
* IPA + foam swabs for connector cleaning.
* IPA and foam swabs for connector cleaning.
* Soldering iron with fine tip + solder wick for RTC and capacitor work.
* Fine-tipped soldering iron and solder wick for RTC and capacitor work.
* Spare Dallas DS12887+ for Model 30 286 RTC.
* A replacement RTC module for a Model 30 286, or a fresh BR-2/3A-format 3 V lithium cell for an 8086 riser.
* Period-correct or modern equivalent Model 30 Reference Diskette image (model-specific).
* A written copy of the model-specific Reference or Starter Diskette.
* Plastic crowbar / spudger for the captive push-pin fittings.
 
See also [[Recommended Tools]].


== Related Pages ==
== Related Pages ==
Line 143: Line 289:
* [[IBM PS/2 Model 30 Troubleshooting Guide]]
* [[IBM PS/2 Model 30 Troubleshooting Guide]]
* [[IBM PS/2 Model 30 Capacitor Replacement Guide]]
* [[IBM PS/2 Model 30 Capacitor Replacement Guide]]
* [[IBM PS/2 Model 25 Maintenance Guide]] &mdash; sister all-in-one
* [[IBM PS/2 Model 25 Maintenance Guide]] &mdash; the all-in-one sister machine
* [[Recommended Tools]]
* [[Hard Drive Maintenance and Repair]]
* [[Floppy Drive Repair]]


== References ==
== References ==


* [https://www.dosdays.co.uk/computers/IBM%20PS2%20Model%2030/ibm_ps2_model_30.php IBM PS/2 Model 30 &mdash; DOS Days]. Source for the PSU rating (70 W), proprietary ST-506 hard drive interface, ISA-only expansion, drive caddy and Sony 1.44 MB compatibility.
<references />
* [https://www.ardent-tool.com/qtechinfo/8530.html IBM PS/2 Model 30 Quick Reference], Ardent Tool of Capitalism. Source for the submodel list, FRU details and the captive push-pin mechanism.
* [https://www.ardent-tool.com/trouble/ps2error.html PS/2 Error Codes], Ardent Tool. Reference for the 161/162/163 RTC cluster and the dead-system isolation procedure.
* IBM, ''IBM Personal System/2 Hardware Maintenance Reference'' (S52G-9971 series).


{{Navbox-IBMComputers|state=collapsed}}
{{Navbox-IBMComputers|state=collapsed}}

Latest revision as of 08:59, 27 September 2026

An IBM PS/2 Model 30 286 (8530-E series). The 286 machines are the ones with a voltage selector switch on the rear and a Dallas RTC module on the planar. (Image: DigitalIceAge, CC BY 4.0, via Wikimedia Commons)

This guide documents preventive maintenance on the IBM PS/2 Model 30 (machine type 8530), covering both the original Model 30 8086 (8530-002 and 8530-021) and the later Model 30 286 (8530-E01, E21, E31, E41). The Model 30 is a desktop-form-factor PS/2 with no integrated CRT, unlike the Model 25, so the system unit can be opened and worked on at the bench with far less electrical risk.

Safety Warning

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The power supply rectifies the mains directly and its bulk capacitor holds that charge after the lead is pulled — roughly 170 V on a 120 V mains, roughly 325 V on a 230 V mains. Before any work inside the supply's shell:

  1. Power off and unplug the mains lead.
  2. Bleed the bulk capacitor through a resistor across its terminals (1 kΩ / 5 W is the usual workshop choice).
  3. Confirm on a DC range that it is down to a few volts.

If your machine is a Model 30 286, check the voltage selector switch on the rear before plugging the cord in. It must be set to the 100–125 Vac or the 200–240 Vac range to match your supply.[1][2] The 8086 Model 30's supply is the internal-sensing type and has no switch.[3]

There is no CRT inside the Model 30 itself, so the anode-discharge procedure needed on the Model 25 does not apply unless you are servicing the matching PS/2 display, in which case see CRT Discharge Procedure.

Identifying Your Model

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Model 30 generation identification
Marker Model 30 8086 Model 30 286
Machine types 8530-002, 8530-021 8530-E01, E21, E31, E41
CPU Intel 8086-2 at 8 MHz, at planar U10 Intel 80286 at 10 MHz, at planar ZM36 (PGA socket on early boards, PLCC on later)
Chipset IBM gate arrays VLSI VL82CPCAT-QC, at ZM2–ZM6
Video MCGA VGA
Riser three 8-bit ISA slots 16-bit ISA
Extra bus power connector absent present (J14, 4-pin, feeds the 16-bit bus)
Real-time clock NS MM58167AN at planar U16, battery on the riser card Dallas DS1287 module at ZM35, cell sealed inside
Diskette drive as shipped 720 KB 1.44 MB
Power supply 70 W, internal sensing, no voltage switch 90 W, dual voltage, switch on the rear

Sources for this table: the planar designator maps,[4][5] IBM's announcement letters,[3][2] and IBM's Technical Reference.[6]

The machine type and submodel are printed on the rear panel label, for example "Type 8530-E21".

Planar Layout

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The 8086 planar exists as the original "P-PLANAR" P/N 61X8823 and two later Greenock builds, P/N 33F4888 and FRU P/N 33F8474 (P/N 33F4871). The layouts look nothing like each other, but the reference designators are largely consistent across all of them — and across the 8086-based Model 25 planars too, which makes this map useful on either machine.[4]

Model 30 8086 planar — principal designators
Designator Device
J1 / J2 Mouse / keyboard connectors (Mini-DIN-6, not interchangeable)
J3 Parallel port (DB-25)
J4 Video connector (HD-15)
J5 Serial port (DB-25)
J6 Riser slot
J7, J9 Power connectors
J10 2-pin keylock header
J11 44-pin fixed-disk connector
J12 40-pin diskette connector
J13 Dual 30-pin SIMM socket
F1 / F2 Mouse and keyboard fuses (combined into F1 on the later alternative Greenock board)
U5 Inmos IMSG171S RAMDAC
U8 Intel P8253-5 timer
U10 Intel 8086-2 CPU, 8 MHz
U13 8087 coprocessor socket
U16 NS MM58167AN real-time clock
U17, U20 ROM BIOS (even / odd)
U18 NEC µPD765AC diskette controller
U19 8237A DMA controller
U27 NS8250AV UART
SP1 Piezo speaker
Y1 / Y2 / Y3 14.31818 MHz / 25.175 MHz / 48.000 MHz oscillators
Y4 32.768 kHz crystal (real-time clock)

On the 286 planar the numbering changes to a ZM prefix: ZM2 VL82C100 peripheral controller, ZM3 VL82C102A memory controller, ZM4 VL82C103A address buffer, ZM5 VL82C104 data buffer, ZM6 VL82C101B system controller, ZM9 VL16C451 parallel/UART, ZM19 µPD765AC-2 diskette controller, ZM33 8042/8742 keyboard controller, ZM35 Dallas DS1287 RTC/CMOS, ZM36 the 286 CPU. Power arrives at J7 and J14, and J13 is the password-override jumper.[5]

Opening the System Unit

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Tools: a Philips screwdriver, an anti-static strap and a plastic spudger.

  1. Turn off the system unit and every external option.
  2. Unplug the system unit's power cord from the outlet, then the cords of any external options.
  3. Remove all cables from the rear of the system unit.
  4. If the machine has a cover lock, unlock it and remove the key.
  5. Loosen the two cover screws and lift the cover off.[7]
A Model 30 286 with the cover off. The drive cage sits over the planar, the power supply alongside it, and the riser card at the rear. Drives and cards are held by plastic captive push-pin fittings, not screws. (Image: DigitalIceAge, CC BY 4.0, via Wikimedia Commons)

Inside, the drive cage sits over the planar and the supply is alongside it; the riser card mounts at the rear. Cards on the riser and the drives are held by IBM's plastic captive push-pin fittings. Lever these with a plastic spudger, never a metal screwdriver — the pins are brittle with age and snap, and a broken captive pin means the drive cage no longer locates properly.

Regular Cleaning

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  • Soft brush and low-pressure compressed air for the planar, riser, drives and supply vents. Hold any fan blades still by hand while blowing, so the fan is not spun beyond its rated speed.
  • Clean the Mini-DIN-6 keyboard and pointing-device connectors with a deoxidising contact cleaner on a foam swab, sparingly.
  • Clean the DB-25 parallel and serial connectors.
  • Inspect the planar for leaked electrolyte, and the diskette drive boards more carefully still — that is where PS/2 capacitor damage actually shows up. See IBM PS/2 Model 30 Capacitor Replacement Guide.

PSU Voltage Checks

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Power reaches the planar through two 6-pin connectors, P3 and P4. P3 is the one nearer the rear of the system.[6]

Model 30 power supply connector pin assignments
Pin P3 P4
1 Power Good Ground
2 Ground Ground
3 +12 V dc −5 V dc
4 −12 V dc +5 V dc
5 Ground +5 V dc
6 Ground +5 V dc

Measure with the system powered on and running. IBM's service limits are given between specific pins, so put the meter's negative lead where the table says:

Model 30 and Model 30 286 — service measurement limits
Rail Negative lead Positive lead Minimum Maximum
+5 V P3-5 P4-4 +4.8 V +5.2 V
−5 V P4-3 P3-6 +4.6 V +5.5 V
+12 V P4-1 P3-3 +11.5 V +12.6 V
−12 V P3-4 P4-2 +10.8 V +13.2 V

The negative rails are measured with the leads reversed, which is why they read as positive numbers.[1]

The supply shuts itself down if a rail falls below its under-voltage sense level: +4.5 V on the +5 V rail, −4.3 V on −5 V, +10.8 V on +12 V and −10.2 V on −12 V.[6][1] A rail sitting just above its trip point will run on the bench and then drop the machine as soon as it is loaded.

Power Good should read +3.5 V to +5 V at P3-1 when the system is operating correctly. If it does not, strip out all adapters, cables and extra memory and try again; if Power Good comes up, one of those devices was shorting a rail, and you find it by reinstalling them one at a time.[1] IBM specifies the line as TTL-compatible, active at 2.4 to 5.25 V dc, inactive at 0.0 to 0.4 V dc, with a turn-on delay of not less than 100 ms and not more than 500 ms.[6]

The Model 30 286's supply adds the 4-pin bus power connector; other than that connector the two supplies are interchangeable in the chassis.[8] Do not fit a Model 25 supply: the Model 25 8086 does not use the same power connector as the Model 30 8086.[9]

Real-Time Clock and Battery

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Both generations have a hardware real-time clock. IBM lists "Real-time clock with battery" among the 8086 Model 30's integrated system-board functions, with the clock at I/O addresses hex 00B0–00BF (command/status) and hex 00E0–00EF (counter/RAM).[6]

Model 30 8086

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The clock is a National Semiconductor MM58167AN at planar position U16, timed by the Y4 32.768 kHz crystal.[4]

The cell that backs it is not on the planar. It is a 3 V lithium Panasonic BR-2/3A soldered to the riser card at B1 — riser P/N 61X8864 or 61X8910, which also carries the three 8-bit ISA slots and, apart from the battery, nothing else of consequence.[4] If the clock on an 8086 Model 30 will not hold time, pull the riser, not the planar. This catches people out: the riser is the last place most restorers look for a battery.

IBM's own service notice on the subject is worth knowing about, because the early manual got it wrong. Retain tip H067282 records that early releases of the 8530 Hardware Maintenance Service manual, on system board map page 0100-4, label the bus adapter card's pins incorrectly: the pins printed as "0" and "39" are actually pins 1 and 40, and the voltage should be measured at pins 38 and 39 — the second and third pins in from the right-hand edge. Replace the bus adapter card if the voltage between the correct pins is below 2.5 V.[4]

Model 30 286

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The clock is a Dallas DS1287 RTC/CMOS module at ZM35, a 24-pin DIP with the lithium cell sealed inside it.[5] When the cell runs down, POST reports:

  • 161 — battery. IBM's FRU order for this code is battery, then complex, then system board, then bus adapter.
  • 162 — configuration changed; check that all devices are powered on and that the configuration has not been altered, then run Automatic Configuration. If that does not clear it, suspect the battery.
  • 163 — date and time error; set the date and time.
  • 167 — clock not running correctly.
  • 168 — real-time clock error; run Advanced Diagnostics. This is not always a hardware failure.[10]

Replacement is by desoldering the 24-pin DS1287 and fitting a fresh DS12887+ or equivalent; some restorers instead cut into the original module's case to reach the cell and fit an external holder. IBM's own caution on the 161 code is worth repeating: the lithium cell presents a fire, explosion and burn risk — do not heat, crush, short or recharge it.[10] See Battery Refurbishment and Battery Explosion, Capacitor or Corrosion Damage.

After either job, boot the Reference or Starter Diskette and run Set Configuration to re-enter memory size, drive type and the date and time.

Power-on password

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If the power-on password on a Model 30 286 is forgotten, move the J13 jumper on the planar to its other position: if it covers the first and second pins, move it to the second and third, and vice versa. Leave it where you moved it until the next time it needs resetting.[7][5]

Connector Care

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  • Keyboard and pointing device (Mini-DIN-6): these are two physically identical sockets with different functions — J1 is the mouse, J2 the keyboard.[4] They are not interchangeable. The plastic key aligns the plug; do not force it.
  • Keyboard and mouse fuses: F1 and F2 on the planar protect the +5 V feed to the two ports, combined into a single F1 on the later alternative Greenock board.[4] A 305 at POST is a keyboard voltage error, and IBM's first FRU for it is the keyboard port fuse.[10]
  • Parallel port (DB-25) and serial port (DB-25 on the 8086 planar) are conventional.[6][4]

Single-Cable Drive Interface

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The PS/2 drive interface carries power and data in one ribbon cable from the planar to the drive; there are no Molex connectors anywhere in the machine.[8] IBM's published pin assignments show exactly where the power sits:

  • Diskette (J12, 40-pin): pin 38 is +5 V dc and pin 40 is +12 V dc; odd-numbered pins 1 to 35 are signal ground.[6]
  • Fixed disk (J11, 44-pin): pins 30 and 32 are +5 V dc, pins 40, 42 and 44 are +12 V dc.[6]

Care points:

  • Align the cable's stripe to pin 1 at both ends.
  • Because the supply rails ride on the same connector as the data lines, a mis-inserted or offset cable puts +12 V onto signal pins. Check the alignment twice before powering up.
  • The drives have no dust shutter, so dust reaches the heads. Clean periodically.[9]

Diskette Drive Maintenance

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  • The 8086 machines shipped with 720 KB drives and the 286 machines with 1.44 MB.[3][2] You can tell which you have from the blue eject button: a high-density drive has "1.44MB" moulded into it.[8]
  • Use DSDD media in a 720 KB drive. A 662 at POST means the wrong drive type is installed and a 663 means the wrong media type is in the drive; 604 means an unsupported drive or cable, the drive having to be a media-sense type.[10]
  • IBM never shipped the 8086 Model 30 with a high-density drive, but the machine does have undocumented 1.44 MB support. Sony-manufactured drives are the ones likely to work; other makes are recognised only as low-density, or not at all. Which planar you have also matters — the later boards are more tolerant.[9][8]
  • These drives have no belt. The Mitsubishi MF355C family rotates the disk with a DC brushless direct-drive motor coupled straight to the spindle at 300 rpm.[11] A drive that will not spin or spins slowly needs its board and motor examined, not a belt.
  • The real wear item is the surface-mount electrolytics on the drive logic board, which leak and corrode the board underneath. See IBM PS/2 Model 30 Capacitor Replacement Guide and Floppy Drive Repair.

Fixed Disk Maintenance

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The Model 30's fixed-disk interface is not ST-506, not ESDI and not IDE. IBM describes J11 as a dedicated I/O channel: it carries the ordinary I/O channel signals needed for fixed-disk operation — I/O read and write, reset, the data lines, I/O CH RDY, IRQ5 and the DMA request and acknowledge lines — plus a −DISK CS card-select decoded at hex 032x, a −DISK Installed line and address lines A0 to A2 to select a register inside the controller.[6] The controller is on the drive, not on the planar: IBM's own announcement describes the 8530-021 as shipping with "one 20MB fixed disk with integrated controller".[3][8]

In practice:

  • Only the original IBM drive assemblies are recognised, and the setup diskette offers no other drive types.[8]
  • Those drives are failure-prone. If one will not spin up, suspect head stiction; rotating the drive body by hand with the power off sometimes frees it, but treat that as a way to get the data off, not as a repair.
  • Practical replacements are an XT-IDE card on the ISA bus, an SD-based emulator, or an MFM emulator — all of which sidestep the planar interface entirely.
  • The drive sits in a metal caddy held by the same plastic captive push-pin mechanism as everything else.[8]

IBM issued a service notice about drive and board combinations on these machines. Retain tip H007157 records that successful fixed-disk operation on the 8530-001 and -021 depends on matching the system board, the drive and the version of Advanced Diagnostics used to format it — and that formatting with the wrong version of the diagnostics causes fixed-disk errors:[4]

IBM retain tip H007157 — required FRU combinations
Machine type System board Fixed disk Advanced Diagnostics
8530-021 below serial 2500000 P/N 61X8907 P/N 61X8929 8530, any version
8530-021 above serial 2500000 P/N 33F8474 P/N 6128285 8530, version 1.05
8530-001, all P/N 33F8474 P/N 6128285 or 6128279 8530, version 1.05
8530-E21 only P/N 27F4069 P/N 6128285 8530-286, version 1.02
8530-E31 and E01 P/N 34F0046 P/N 6128285 or 6128279 8530-286, version 1.02

Fixed disks P/N 6128285 and 6128279 must not be installed in any 8530-021 below serial number 2500000.[4]

Known IBM Service Notices

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Three more IBM notices are worth checking before chasing a fault on an 8530.

  • H043664 — cursor keys and 501 POST errors. On a limited number of 8530-001 and -021 machines, the cursor keys produce unexpected characters on the display, and a 501 appears when two or more option cards are fitted. Inspect the modules at planar positions U9 (next to the coprocessor socket) and U15 (next to the speaker). U9 P/N 72X8203 and U15 P/N 61X8965 are suspect if they are marked "IBM" but do not carry the word "Japan"; good parts have it. IBM's fix was to replace the system board with FRU P/N 64F3453. Machines with serial numbers above 55-00HV000 already have the new board.[4]
  • H094152 — 8515 and 8516 displays. The 8086 Model 30 (models 001, 002 and 021) does not support PS/2 8515 or 8516 displays; attaching one gives compressed, distorted video. It does support the 8503, 8504, 8507, 8512, 8513 and 8514. The 286 machines (E01, E21, E31, E41) support the 8503, 8504, 8512, 8513, 8514, 8515 and 8516.[4]
  • H036143 — 8602 with a 4717 printer. On a Model 30 286 shipped after 1 August 1989, attaching a 4717 directly gives an 8602 POST error and the printer does not work, because a planar change grounded pin 2 of the pointing-device port. IBM's fix was an interposer cable, P/N 31F6759.[5]

Things That Are Not Faults

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  • An 8086 Model 30 will not drive an 8515 or 8516 display properly. That is a documented limitation, not a fault.[4]
  • A 162 after you have added or removed a device is the machine noticing the change. Run Set Configuration before suspecting the battery.[10]
  • Soft-booting the Reference Diskette with Ctrl-Alt-Del can throw false errors and a false indication that a power-on password is already set. Cold boot with the diskette in the drive.[10]
  • A 663 means the diskette in the drive is the wrong media type for that drive. It is information, not a failure.[10]

Capacitor Health

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Tantalum beads on the planar can fail short and stop the supply from coming up; aluminium electrolytics on the diskette drive boards leak and corrode. Full procedures, including what is and is not documented about this machine's capacitors, are in IBM PS/2 Model 30 Capacitor Replacement Guide.

[edit | edit source]
  • Philips screwdriver and an anti-static strap.
  • Plastic spudger for the captive push-pin fittings.
  • Digital multimeter.
  • IPA and foam swabs for connector cleaning.
  • Fine-tipped soldering iron and solder wick for RTC and capacitor work.
  • A replacement RTC module for a Model 30 286, or a fresh BR-2/3A-format 3 V lithium cell for an 8086 riser.
  • A written copy of the model-specific Reference or Starter Diskette.

See also Recommended Tools.

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References

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  1. ↑ 1.0 1.1 1.2 1.3 Louis Ohland, Tomáš Slavotínek et al., "8525 / 8530 Power", Ardent Tool of Capitalism, https://www.ardent-tool.com/8530/Power.html. Transcribes IBM's Hardware Maintenance Service data for the 8525 and 8530: the P3/P4 and J7 connector measurement limits, the minimum under-voltage sense levels, the power-good range and the dead-system isolation procedure, and the warning that the manually-switchable supply must be set before the cord is plugged in.
  2. ↑ 2.0 2.1 2.2 IBM Announcement Letter 189-035, Personal System/2 Model 30 286 (8530-E01). Gives the 90-watt dual-voltage power supply with a switch on the rear, the 90–137 Vac and 180–265 Vac input ranges, the 10 MHz 80286, VGA graphics and the 1.44 MB diskette drive.
  3. ↑ 3.0 3.1 3.2 3.3 IBM Announcement Letter 187-048, IBM Personal System/2 Model 30 (8530-002, -021), 2 April 1987. Gives the "Universal 70W power supply, with internal sensing, for worldwide usage", and the 8530-002 (two 720 KB diskette drives) and 8530-021 (20 MB fixed disk with integrated controller plus one 720 KB diskette drive) configurations.
  4. ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 Louis Ohland, Tomáš Slavotínek et al., "8530 Planar (8086)", Ardent Tool of Capitalism, https://www.ardent-tool.com/8530/Planar.html. Gives the "P-PLANAR" P/N 61X8823 designator map, the two Greenock planar variants (P/N 33F4888 and FRU P/N 33F8474 / P/N 33F4871), the ROM image list, the riser card part numbers (61X8864, 61X8910) and its B1 3 V lithium battery (Panasonic BR-2/3A), the note that reference designators are largely consistent across all 8086-based Model 30 and Model 25 planars, and IBM retain tips H007157, H043664, H067282 and H094152.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Louis Ohland, Tomáš Slavotínek et al., "8530 286 Planar", Ardent Tool of Capitalism, https://www.ardent-tool.com/8530/Planar_286.html. Gives the full 8530-286 planar designator map (VL82CPCAT-QC chipset at ZM2–ZM6, VL16C451 at ZM9, DS1287 RTC/CMOS at ZM35, 8042/8742 keyboard controller at ZM33, 286-10 CPU at ZM36), the early PGA and later PLCC builds with FRU P/N 34F0046, the J13 password-override jumper and IBM retain tip H036143.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 IBM, IBM Personal System/2 Model 30 Technical Reference, January 1987. File:IBM PS2 Model 30 Technical Reference Jan87.pdf. Section 1 lists the system board's integrated I/O functions, including "Real-time clock with battery", the I/O address map (real-time clock at hex 00B0–00BF and 00E0–00EF), and the diskette and fixed-disk connector pin assignments. Section 3 "Power Supply", pages 3-3 to 3-6, gives the 70 W rating, rail currents, regulation tolerances, under-voltage sense levels, power-good characteristics and the P3/P4 pin assignments.
  7. ↑ 7.0 7.1 IBM, Personal System/2 Model 30 286 Guide to Operations, first edition, September 1988. IBM PS/2 Model 30 286 Guide to Operations (PDF). "Cover Removal", page 2-2, and "Power-on Password Reset", pages 3-4 and 3-5, which locate the J13 jumper on the system board and describe moving it between the first-and-second and second-and-third pin positions.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 "IBM PS/2 Model 30", DOS Days, https://www.dosdays.co.uk/computers/IBM%20PS2%20Model%2030/ibm_ps2_model_30.php. Source for the single-cable drive interface with no Molex connectors, the extra 4-pin bus power connector on the Model 30 286, the statement that the fixed-disk interface is neither ESDI nor standard MFM, the drive caddy, and the Sony 1.44 MB drive compatibility note including the "1.44MB" marking on the eject button.
  9. ↑ 9.0 9.1 9.2 Louis Ohland, William R. Walsh, Tomáš Slavotínek et al., "8525 Planar", Ardent Tool of Capitalism, https://www.ardent-tool.com/8525/Planar.html. Gives the Model 25 planar designator maps, the warning that the Model 25 8086 does not use the same power connector as the Model 30 8086, the riser card contents, and William Walsh's account of the surface-mount electrolytic failures on PS/2 diskette drives and of undocumented 1.44 MB support with Sony drives.
  10. ↑ 10.0 10.1 10.2 10.3 10.4 10.5 10.6 "PS/2 Error Codes" and the error code listings, Ardent Tool of Capitalism, https://www.ardent-tool.com/trouble/ps2error.html. Error codes 160–199 (https://www.ardent-tool.com/trouble/error_02.html) and 300–999 (https://www.ardent-tool.com/trouble/error_04.html) give the 161/162/163/167/168 battery and clock cluster, the 301–307 keyboard cluster, 305 "keyboard voltage error" with the keyboard port fuse as the first FRU, and the 601–668 diskette cluster including 604 "unsupported drive or cable" and 662 "wrong drive type installed". The main page gives the dead-system isolation procedure.
  11. ↑ Mitsubishi Electric, 3.5 inch Flexible Disk Drive Standard Specifications, MF355C, document UGD-0527A, February 1987. File:Mitsubishi MF355C 3.5 inch Diskette Drive Specifications (UGD-0527A, Feb 1987).pdf. Section 3 states that the disk rotation mechanism uses a DC brushless direct-drive motor to rotate the spindle directly at 300 rpm.