IBM PS/2 Model 60 Maintenance Guide
Routine service on the IBM PS/2 Model 60 (machine type 8560) covers a floor-standing tower announced on 2 April 1987 in two submodels: the 8560-041 with a 44 MB ST-506 fixed disk and the 8560-071 with a 70 MB ESDI fixed disk.[1] The chassis and the power-supply family are shared with the Model 65 SX and the IBM PS/2 Model 80, so most of the mechanical work applies to those as well.[2] The machines are now more than 35 years old; the jobs that matter most are cleaning dust out from under the supply fan, checking the battery, and looking after the diskette drive.
Safety
[edit | edit source]The supply rectifies the mains. In the 225 W unit the two primary reservoir capacitors are in series across the rectified mains so that the supply can run on 220 V, and they hold a dangerous charge after the machine is unplugged.[3] If you open the supply, discharge each capacitor through a resistor (for example 1 kΩ, 5 W) and check with a meter before touching the board. The procedure is in the IBM PS/2 Model 60 Capacitor Replacement Guide.
The supply selects its input range automatically, so there is no voltage switch to set.[1] There is no CRT in the system unit; for an IBM display, see CRT Discharge Procedure.
The tower weighs 20 kg with one fixed disk, according to IBM's Technical Reference; IBM's later specification sheet gives 21.3 kg. Lift it with help.[4][5]
Specifications
[edit | edit source]| Item | Value |
|---|---|
| Size | 165 mm wide (318 mm with the feet extended), 483 mm deep, 597 mm high |
| Weight | 20 kg with one fixed disk |
| Heat output | 363.4 W |
| Mains input | 90–137 V or 180–265 V, 50–60 Hz ±3 Hz, selected automatically |
| Maximum current | 5.3 A on the low range, 2.7 A on the high range |
| Keyboard port, maximum load | 275 mA |
| Auxiliary device port, maximum load | 300 mA |
| Micro Channel | Eight connectors, 8- or 16-bit devices; one with the auxiliary video extension, one used by the fixed-disk adapter |
| Drive bays | Two 3.5-inch half-height, two 5.25-inch full-height |
| System-board memory | 1 MB as four 30-pin 256 KB parity modules (FRU 61X8906) |
Sources: IBM's Technical Reference, specification sheet and parts list.[4][5][6]
Opening the system unit
[edit | edit source]Tools: a coin or a large flat-blade screwdriver, a cross-head screwdriver and an anti-static strap.
- Power off and unplug everything.
- Turn the two large screws on the side cover to the left. They are captive and will not come out.
- Pivot the cover on its bottom hinges until the top edge clears the case, then lift it up and out.[7]
To remove the front bezel, open the side cover and pull the battery and speaker assembly out sideways by its frame. Do not pull the battery lead off the planar, or the configuration is lost; lay the assembly in the bottom of the case. Press the white plastic catch below the grille down and towards the front; the second catch is behind the black foam at the inner edge of the grille. With both catches free, pull the bottom edge of the bezel off.[7]
If the cover is locked and the key is lost, Ardent Tool gives Tony Ingenoso's method. Turn the machine upside down, remove the front bezel, loosen the lowest slot retainer and push the slot blank into the case. Then, with a torch and a long thin screwdriver, press down the front and rear retaining tabs of the side cover through the slot opening and one of the bezel holes, shimming the cover as each tab releases. A card in the bottom slot makes this harder. The alternative is to drill two small holes in the base over the tabs; measured on an 8580, the front tab is 2.8 inches from the front corner and 1.5 inches in, the rear tab 3.6 inches from the back and 1.5 inches in, both about 0.25 inches deep. Use a depth stop, or you drill through the tab.[7]
The Micro Channel connectors are on the planar itself.[8][6]
Cleaning
[edit | edit source]Ardent Tool records a common cause for lost configuration, a clock showing nonsense after a long power-off, and fixed disks with read/write errors that a new battery does not cure: dust on the planar under the supply fan. On a Model 80 board that area holds the keyboard controller, the MC146818A clock and CMOS RAM, the diskette controller, the NS16550 serial controller, the 32.768 kHz clock crystal and sometimes an 8259A interrupt controller, and the dust is usually conductive. The remedy is to strip the machine, blow the supply out with compressed air and a fine nozzle (outdoors; a lot of dust comes out), then brush and vacuum the planar, looking for dust packed between IC pins. Reassemble, start the Reference Diskette, set the date, time and configuration, and test again.[7] Fred Spencer adds that dirt on the diskette controller leaks current between its pins and gives 6xx errors that look like a failed drive.[9]
PS/2 diskette drives have no shutter over the slot and collect dust.[7]
Power supply checks
[edit | edit source]The 041 was fitted with a 207 W supply and the 071 with a 225 W supply. IBM's 1994 parts list gives one replacement for all Models 60, 65 and 80, FRU 57F1600, which Ardent Tool lists as a 250 W unit; a 242 W supply was also used in later 8580s. All share one form factor and pinout.[5][6][2] The 225 W unit, IBM P/N 72X6665, is labelled 100–125 V 4.5 A or 200–240 V 2.5 A input, and +12 V 7 A, +5 V 27.25 A and −12 V 0.39 A output.[2]
The supply has three outputs, +5 V, +12 V and −12 V. It connects to the planar with a 15-pin connector and to each fixed disk with a 4-pin connector.[10]
| Pins | Signal |
|---|---|
| 1, 4, 7, 10, 13 | +5 V |
| 2, 5, 6, 8, 11, 14 | Ground |
| 3 | +12 V |
| 9 | −12 V |
| 12 | Power Good |
| 15 | System status (IBM); Ardent Tool identifies it as the hard-disk LED line |
Sources: IBM's Hardware Interface Technical Reference and Ardent Tool.[10][2] The fixed-disk connectors carry +12 V on pin 1, ground on pins 2 and 3 and +5 V on pin 4.[10]
IBM's test limits, with the negative lead on pin 2 of the system-board connector or pin B of a drive connector:[6]
| Output | + lead | Minimum | Maximum |
|---|---|---|---|
| −12 V | Pin 9 | −9.0 V | −15.0 V |
| +12 V | Pin 3 | +9.0 V | +15.0 V |
| +5 V | Pin 1 | +3.7 V | +6.2 V |
| +5 V | Drive connector pin D | +3.7 V | +6.2 V |
| +12 V | Drive connector pin A (− lead on pin C) | +9.0 V | +15.0 V |
Ardent Tool's copy of the table adds that the 15-pin connector should be unplugged from the planar before taking the drive-connector readings, and that the supply should be replaced if the readings are wrong or the fan is not running.[2] These limits are IBM's pass/fail test for replacing the supply. IBM's Model 60 documents give no under-voltage sense levels; the Model 50's figures belong to a different supply.
The protection that IBM describes for all PS/2 supplies:[6][10]
- A short between an output and ground or between two outputs, an overcurrent, or an overvoltage before any output reaches 130 % of nominal shuts the supply down. It restarts only when the power switch has been off (at least ten seconds, for the Type 1 and 2 supplies) and the fault is gone.
- If any output falls below its regulation range, Power Good drops and the system stops. The green front LED shows that the supply is operating.
- Most PS/2 supplies restart by themselves after a mains outage.
In the 225 W unit the green LED is driven from Power Good, and trimmer R77 sets +5 V and +12 V together.[3]
To remove the supply, take the rear drive carrier out of the drive support structure, unplug any 4-pin drive power leads and the planar power plug, remove the three screws holding the supply and pull it out.[2] The Model 50's supply cannot be fitted: it is IBM's Type 1, with a 50-pin card-edge connector, where the Model 60 uses the Type 2 with cables.[10]
Peter Wendt reports that half of the Model 80 supplies failed with a broken power switch, the red ones more often than the white; the switch was also used in IBM 327x and 525x terminals and was available as a spare part. A crackle from a switched-off machine can come from the switch, the mains filter or a loose mains lead.[2]
Fred Spencer's power table on Ardent Tool, from IBM's Personal System/2 Reference Guide, gives 31–39 W for the 44 MB, 70 MB and 115 MB drives, 35–42 W for the 314 MB drive, and roughly 7–10 W for each IBM 16-bit adapter. A 207 W machine with two full-height drives and several adapters is near its limit.[2]
Battery and clock
[edit | edit source]The clock is a Motorola MC146818A on the planar (ZM6) with 64 bytes of CMOS RAM, 14 of them used by the clock. A 2 KB CMOS RAM extension (ZM5) holds further configuration. A 6 V lithium battery keeps both running when the supply is off.[4][8]
The battery is IBM part 72X8498, a two-cell 6 V lithium pack, in battery and speaker assembly 33F5950, which plugs into J14.[6][8] Camera batteries fit: Ardent Tool lists the CR-P2 (Varta, Panasonic, GP, Sony, Sanyo), Duracell DL223A, Ever Ready EL223AP, Kodak K223LA and Ray-O-Vac PC223.[11]
Testing the battery
[edit | edit source]IBM retain tip H024809, reproduced by Ardent Tool, says intermittent 161, 162 and 163 errors can be caused by low battery voltage or a faulty battery and speaker assembly (33F5950):[7]
- Switch the system off.
- Take the battery out of the assembly. Measuring it in the assembly gives a misleading reading.
- Set the meter to the 12 V DC range.
- Replace the battery if it reads below 5.5 V DC.
Alfred Arnold, quoted by Ardent Tool, notes that as the battery fails the clock's 32 kHz oscillator usually stops before the CMOS contents are lost. A machine that powers up showing the time at which it was switched off, with no 161 or 163 yet, has a battery near the end of its life.[7]
Replacing the battery
[edit | edit source]On the Models 60, 65 SX and 80 the assembly slides out towards the open side of the case. The battery's contacts face the rear, against the spring clips.[12] IBM's Model 50 manual, for the same assembly and battery, says to use only part 72X8498, to take the battery out before disconnecting the assembly cable, and to connect the cable before refitting the battery, so that the battery is not discharged by accident.[13] Afterwards, start the Reference Diskette and restore the configuration, date and time.
Error codes
[edit | edit source]| Code | IBM's note | FRU / action |
|---|---|---|
| 161 | Battery | Battery; system board; bus adapter |
| 162 | Be sure all devices are powered on; check the Enable/Disable settings. If the configuration has changed, run Automatic Configuration | Any device; battery |
| 163 | Date and time error | Set the date and time |
| 164, 165, 167 | If setting the configuration, date and time does not cure it, check the devices list | Set configuration and features; system board |
| 166 | Reseat all adapters | Run Advanced Diagnostics |
| 168 | Real-time clock error; not always a hardware failure | Run Advanced Diagnostics |
| 173 | Possibly a weak battery | Set configuration and features |
The Model 60 has no clock module; its clock chip is soldered to the planar.[8] Before replacing parts for a 16x error, clean the planar under the supply fan.[7] The full code list is in the Model 50 troubleshooting guide.
Power-on password
[edit | edit source]To clear an unknown power-on password, power off and unplug the machine, short pins 2 and 3 on the battery and speaker assembly (on an assembly without pins, connect contact 1 to frame ground), power on, and remove the short once POST has finished.[12]
Connectors
[edit | edit source]- Keyboard (J2) and mouse (J4): 6-pin mini-DIN sockets, protected by fuse F1 (3 A 250 V, IBM FRU 72X8561) on the planar.[8][6] IBM's action for a 305 (keyboard voltage error) is the fuse first, then the keyboard cable.[6]
- Serial (J7, 25-pin) and parallel (J6).[8]
- Micro Channel card edges: clean the contacts and reseat the card before chasing an intermittent fault; IBM's action for 166 is to reseat all adapters.[6]
Diskette drives
[edit | edit source]The Model 60 takes the 1.44 MB half-height drive with the card-edge interface, P/N 90X6766, FRU 72X8523; the later third-height drive is FRU 64F0162.[9][6] IBM's specification for the 1.44 MB drive is 80 tracks at 135 tracks per inch, two heads, 500,000 bit/s in high-density mode, 6 ms track to track, 15 ms settle, 500 ms maximum motor start and 300 rpm ±1.5 %. IBM warns against formatting a 1 MB diskette as 1.44 MB or a 2 MB diskette as 720 KB.[14][1] The drive is direct drive, with no belt.[15]
Peter Wendt, on Ardent Tool, reports that ALPS drives failed much more often than Mitsubishi ones and are harder to take apart, with many tiny cross-head screws. ALPS drives lose the damper pad glued to the head assembly; Mitsubishi 355 drives collect dirt around the head actuator spindle, which makes the head stick.[7] A 162 at POST with an otherwise dead drive is usually mechanical: during POST the heads are stepped away from track 0 and back within a set time, and a sticking carriage, a dirty track-0 sensor or a loose cushion makes the drive miss it. Peter Wendt's grease for the head guides and actuator spindle is Tamiya ball-gear grease.[9]
If the drive reads nothing, or its errors get worse as it warms up, suspect the surface-mount electrolytics on its board; Mitsubishi drives in these machines are noted for capacitors that cause 6xx errors. See the IBM PS/2 Model 60 Capacitor Replacement Guide and Floppy Drive Repair.[7]
Fixed disks
[edit | edit source]| Submodel | Drive (IBM FRU) | Adapter (IBM FRU) | Geometry and timing |
|---|---|---|---|
| 8560-041 | 44 MB ST-506, 5.25-inch full height, 72X8541 | ST-506 fixed disk adapter, 72X8540 | 733 cylinders, 17 sectors, 512 bytes per sector; 5 Mbit/s; 10 ms track to track, 40 ms average, 80 ms maximum |
| 8560-071 | 70 MB ESDI, 5.25-inch full height, 72X8519 | ESDI fixed disk adapter, 92F0061 | 583 cylinders, 36 sectors, 512 bytes per sector; 10 Mbit/s; 5 ms single cylinder, 30 ms average seek, 60 ms maximum |
| Options | 115 MB ESDI (90X7392), 314 MB ESDI (90X8745) | ESDI fixed disk adapter |
Sources: IBM's announcement letter and 1994 parts list.[1][6] The drives connect to the adapter with a control cable (FRU 72X8542) and a signal cable for each drive (72X8545 for drive C, 72X8567 for drive D), and take power through a 4-pin lead (72X8521 single, 34F0034 dual).[6]
- IBM retain tip H064300: for a 1780 on an 8560-041, check that the fixed-disk cables are fitted as shown in the Model 60 maintenance reference.[7]
- A drive that will not spin up after storage has stuck heads. Peter Wendt suggests a few power cycles, or unplugging the system unit, shaking it up and down and turning it sharply clockwise; never lift the front and drop it. Copy the data off as soon as it starts.[16]
- Read errors together with lost configuration: clean the planar under the fan before replacing anything.[7]
- Before moving the machine, park the heads with Move the computer on the Reference Diskette, as IBM's Model 50 manual instructs for the same Reference Diskette.[13][8]
Drive configuration is held in CMOS and set from the Reference Diskette; run Set Configuration after changing a drive.
Micro Channel cards
[edit | edit source]Micro Channel adapters have no switches. Each identifies itself with an adapter ID, and the system sets it up through its Programmable Option Select registers, which IBM says should be set only with the configuration utilities on the Reference Diskette.[4] After fitting, removing or moving a card:
- Copy the adapter's files onto the backup Reference Diskette from its option diskette (Copy an option diskette).[6]
- Start from the Reference Diskette with the diskette in the drive at power-on. A warm boot of the Reference Diskette can give false errors and a false indication that a power-on password is set.[17]
- Run Automatic Configuration, or Set Configuration if the settings were customised.
- Restart and run Advanced Diagnostics if the error persists.
Automatic Configuration can change customised settings. Note them with View configuration first.[6] IBM retain tip H005662 sets rules for the 3270 Connection, Token-Ring and PC Network adapters in the 8560: the 3270 Connection adapter in the lowest free slot, on interrupt 2; the Token-Ring adapter in a higher slot, on interrupt 10 or 11; the PC Network adapter higher still, on interrupt 3. Save the configuration with Backup Configuration afterwards, because Automatic Configuration resets these interrupts to their defaults; Restore Configuration puts them back.[16]
Some non-IBM graphics adapters drive the VGA signals instead of receiving them. Two adapters that both drive VGA signals damage each other.[7]
Capacitor health
[edit | edit source]Ardent Tool's photograph of a 90X8434 planar shows through-hole dipped tantalum and surface-mount ceramic capacitors and no aluminium electrolytics.[8] The parts that age are the surface-mount electrolytics on the diskette drive board and the electrolytics in the supply. See the IBM PS/2 Model 60 Capacitor Replacement Guide.
Recommended tools
[edit | edit source]- A coin or large flat-blade screwdriver for the cover screws, and a cross-head screwdriver
- Anti-static strap
- Digital multimeter
- Compressed air with a fine nozzle, a soft brush and a vacuum cleaner
- The Model 50/60 Reference Diskette and the option diskettes for every fitted adapter[8]
- A spare 6 V battery (72X8498 or a CR-P2 equivalent)[11]
See Recommended Tools for the general kit.
Related pages
[edit | edit source]- IBM PS/2 Model 60
- IBM PS/2 Model 60 Troubleshooting Guide
- IBM PS/2 Model 60 Capacitor Replacement Guide
- IBM PS/2 Model 50 Maintenance Guide
- IBM PS/2 Model 80 Maintenance Guide
- Battery Refurbishment
- Floppy Drive Repair
- Hard Drive Maintenance and Repair
- Recommended Tools
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 IBM Announcement Letter 187-050, IBM Personal System/2 Model 60, 2 April 1987, text at ardent-tool.com. The 041 and 071; automatic voltage-sensing universal supply; eight 16-bit slots with one used by the disk controller; the 44 MB and 70 MB drive specifications; 1.44 MB drive referred to announcement 187-049.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Ardent Tool of Capitalism, "60, 65 SX, and 80 – Power Supply". Removal procedure; planar connector pinout; test-voltage table and notes; supply variants and the 72X6665 label; power-switch failures and crackling; Fred Spencer's device power table.
- ↑ 3.0 3.1 Eric Schlaepfer ("Tube Time"), IBM PS/2 Model 80 Power Supply reverse-engineered schematic, IBM P/N 72X6665, PEC 3978, 2024, CC BY-SA 4.0. Hosted on this wiki as File:IBM PS2 225W Power Supply 72X6665 Reverse-Engineered Schematic (Tube Time 2024).pdf; design notes at github.com/schlae/ps2-80-power.
- ↑ 4.0 4.1 4.2 4.3 IBM, IBM Personal System/2 Model 60 Technical Reference, May 1988. Hosted on this wiki as IBM PS2 Model 60 Technical Reference (May 1988) (PDF). Figure 1-1, p. 1-4; Figure 1-5, "Physical Specifications", p. 1-8; Programmable Option Select warnings, p. 2-3; RT/CMOS RAM and battery, p. 3-10.
- ↑ 5.0 5.1 5.2 IBM, "IBM PS/2 (Model 60) – Technical specifications", document GJAN-43VS3S (2000), mirrored at ardent-tool.com. 207 W (041) and 225 W (071); 21.3 kg; drive bays; four 256 KB modules.
- ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 6.11 6.12 6.13 IBM, IBM Personal System/2 Hardware Maintenance Manual, S52G-9971-02, October 1994. Hosted on this wiki as IBM Personal System 2 Hardware Maintenance Manual (S52G-9971-02, October 1994) (PDF). "Copy an option diskette", p. 23; codes 161–173, pp. 36–37; 305, p. 40; Models 60, 65, 80 power supply check, p. 142; running Automatic Configuration, p. 150; Model 60 system board, p. 200; Models 60, 65 and 80 parts, pp. 252–253; power-supply features, pp. 422–423.
- ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 7.11 7.12 Ardent Tool of Capitalism, "60, 65 SX, and 80 – Common Devices". Opening the case and removing the front bezel; Tony Ingenoso on opening a locked unit; IBM retain tip H064300; dust under the supply fan; IBM retain tip H024809; Alfred Arnold on the clock stopping first; Peter Wendt on ALPS and Mitsubishi drives; the VGA warning.
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 Ardent Tool of Capitalism, "8560 Planar". Designator map of planar FRU 72X8538 (F1, J2, J3, J4, J6, J7, J14, ZM5, ZM6, Micro Channel connectors) and photographs; Model 50/60 Reference Disk v1.08.
- ↑ 9.0 9.1 9.2 Ardent Tool of Capitalism, "8580 Diskette Drives", content by Fred Spencer and Al Savage. Drive part numbers; the diskette controller dirt problem; Peter Wendt on the causes of a 162 and on Tamiya grease.
- ↑ 10.0 10.1 10.2 10.3 10.4 IBM, IBM Personal System/2 Hardware Interface Technical Reference, May 1988. Hosted on this wiki as File:IBM PS2 Hardware Interface Technical Reference May88.pdf. "Power Supply (Types 1 and 2)", pp. 1–5 (PDF pp. 578–582): three outputs; output protection and the ten-second restart; LEDs; Type 1 50-pin card-edge connector; Type 2 15-pin system-board connector and 4-pin fixed-disk connectors.
- ↑ 11.0 11.1 Ardent Tool of Capitalism, "PS/2 RTC/CMOS Batteries", based on content by Bob Eager and Peter H. Wendt. Model 60: FRU 72X8498, a 6 V two-cell lithium pack, with its equivalents.
- ↑ 12.0 12.1 Ardent Tool of Capitalism, "Battery/Speaker Assembly". Models 50, 50 Z, 60, 65 SX, 70 and 80: FRUs 33F5950 (assembly), 57F1437 (8565), 72X8498 (battery); battery orientation; removal on the 60, 65 SX and 80; the power-on password override; connector pinouts.
- ↑ 13.0 13.1 IBM, IBM PS/2 Model 50 Hardware Maintenance Reference, S64F-3989-00, March 1990. Hosted on this wiki as IBM PS2 Model 50 Hardware Maintenance Reference (PDF). Section 2.2, parking the heads with Move the computer; section 6.2, battery and speaker assembly: lithium battery caution, part 72X8498 only, and the order for disconnecting the cable and battery.
- ↑ IBM Announcement Letter 187-049, IBM Personal System/2 Model 50, 2 April 1987, text at ardent-tool.com. The 1.44 MB diskette drive specification, also referenced by the Model 60 announcement.
- ↑ Mitsubishi Electric, 3.5 inch Flexible Disk Drive Standard Specifications, MF355C, UGD-0527A, February 1987. Hosted on this wiki as File:Mitsubishi MF355C 3.5 inch Diskette Drive Specifications (UGD-0527A, Feb 1987).pdf. Section 3: brushless DC direct-drive spindle motor at 300 rpm.
- ↑ 16.0 16.1 Ardent Tool of Capitalism, "Known Problems – Experience, RETAIN Tips, ECAs". Peter Wendt on hard-disk stiction; IBM retain tip H005662 for the 8550, 8555, 8560, 8565, 8570, 8580 and 9585.
- ↑ Ardent Tool of Capitalism, "PS/2 Error Codes". IBM's note on cold-booting the Reference Diskette; running Advanced Diagnostics (Ctrl-A at the main menu) before replacing parts.