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IBM PS/ValuePoint Maintenance Guide: Difference between revisions

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Deep technical PS/ValuePoint pages with verified sources (IBM HMM S61G-1423, kev009 mirror)
ย 
Fix refs so they render: every bare-URL citation converted to a named, labelled reference and deduplicated, and a References list added; -5 V and -12 V tolerances corrected from +/-5 to +/-10 percent
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# Verify with a multimeter.
# Verify with a multimeter.


The PSU is universal-voltage on most submodels but uses a '''manual selector switch''' on the rear (115 V / 230 V). '''Verify the switch position before connecting mains''' โ€” IBM ships boards with the selector at 230 V from the factory, and powering a US 120 V mains into a board set to 230 V will not damage anything but the system will not power on; powering 240 V mains into a board set to 115 V '''will''' destroy the PSU.<ref>http://ps-2.kev009.com/pcpartnerinfo/ctstips/e1f6.htm</ref>
The PSU is universal-voltage on most submodels but uses a '''manual selector switch''' on the rear (115 V / 230 V). '''Verify the switch position before connecting mains''' โ€” IBM ships boards with the selector at 230 V from the factory, and powering a US 120 V mains into a board set to 230 V will not damage anything but the system will not power on; powering 240 V mains into a board set to 115 V '''will''' destroy the PSU.<ref name="s094c49">[http://ps-2.kev009.com/pcpartnerinfo/ctstips/e1f6.htm kev009.com โ€” IBM PS/2 and PC document mirror &mdash; e1f6]</ref>


== Identifying Your PS/ValuePoint ==
== Identifying Your PS/ValuePoint ==
Line 16: Line 16:
The machine type and submodel are printed on the rear-panel label (e.g. "Type 6381-Fxx", "Type 6384-1A3", "Type 6387-Yxx"). The MT maps to a Hardware Maintenance Manual (HMM):
The machine type and submodel are printed on the rear-panel label (e.g. "Type 6381-Fxx", "Type 6384-1A3", "Type 6387-Yxx"). The MT maps to a Hardware Maintenance Manual (HMM):


* '''IBM HMM S61G-1423-01''' (September 1993) โ€” covers 6381, 6382 /S, 6384, 6384 /D, 6384 P60/D, 6387 /T.<ref>http://ps-2.kev009.com/pccbbs/valuepnt/s61g1423.pdf</ref>
* '''IBM HMM S61G-1423-01''' (September 1993) โ€” covers 6381, 6382 /S, 6384, 6384 /D, 6384 P60/D, 6387 /T.<ref name="s984ed3">[http://ps-2.kev009.com/pccbbs/valuepnt/s61g1423.pdf kev009.com โ€” IBM PS/2 and PC document mirror &mdash; s61g1423]</ref>
* '''IBM HMM S61G-1423-02''' (August 1996) โ€” updated HMM covering 638x and the later 64xx transitional machine types.<ref>http://ps-2.kev009.com/basil.holloway/boo-to-pdf/S61G_1423_02.pdf</ref>
* '''IBM HMM S61G-1423-02''' (August 1996) โ€” updated HMM covering 638x and the later 64xx transitional machine types.<ref name="s181a5a">[http://ps-2.kev009.com/basil.holloway/boo-to-pdf/S61G_1423_02.pdf kev009.com โ€” IBM PS/2 and PC document mirror &mdash; S61G 1423 02]</ref>
* '''IBM 6387/T Supplement S71G-1875-00''' (May 1993) โ€” tower-specific supplement.<ref>http://ps-2.kev009.com/basil.holloway/boo-to-pdf/S71G_1875_00.pdf</ref>
* '''IBM 6387/T Supplement S71G-1875-00''' (May 1993) โ€” tower-specific supplement.<ref name="s5deec6">[http://ps-2.kev009.com/basil.holloway/boo-to-pdf/S71G_1875_00.pdf kev009.com โ€” IBM PS/2 and PC document mirror &mdash; S71G 1875 00]</ref>


== Opening the System Unit ==
== Opening the System Unit ==
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=== Cover Lock ===
=== Cover Lock ===


Some PS/ValuePoints ship with a '''cover lock''' that requires a small key to open. Several systems were shipped from the factory '''without''' cover lock keys; if a system arrives with the lock present but no key, order a replacement cover lock assembly from IBM (or a modern locksmith can drill it out).<ref>http://ps-2.kev009.com/pcpartnerinfo/ctstips/e1f6.htm</ref>
Some PS/ValuePoints ship with a '''cover lock''' that requires a small key to open. Several systems were shipped from the factory '''without''' cover lock keys; if a system arrives with the lock present but no key, order a replacement cover lock assembly from IBM (or a modern locksmith can drill it out).<ref name="s094c49" />


=== Cover Switch / Interlock ===
=== Cover Switch / Interlock ===


Some PS/ValuePoint chassis carry a cover-interlock switch โ€” '''the system will not power on or power off if the cover is not seated properly'''.<ref>http://ps-2.kev009.com/pcpartnerinfo/ctstips/e1f6.htm</ref> If the system refuses to power on with the cover off, depress the cover-interlock pin manually with a screwdriver for a smoke-test.
Some PS/ValuePoint chassis carry a cover-interlock switch โ€” '''the system will not power on or power off if the cover is not seated properly'''.<ref name="s094c49" /> If the system refuses to power on with the cover off, depress the cover-interlock pin manually with a screwdriver for a smoke-test.


== Inspecting the Planar ==
== Inspecting the Planar ==
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# '''Lithium battery at B1 / BT1''' โ€” verify the CR2032 cell is seated and shows no leakage. Replace if voltage is below 2.8 V.
# '''Lithium battery at B1 / BT1''' โ€” verify the CR2032 cell is seated and shows no leakage. Replace if voltage is below 2.8 V.
# '''Floppy drive logic board''' โ€” the Alps floppy drive used in many 6381-Fxx and similar boards has an SMD aluminium electrolytic capacitor next to the power connector that '''can leak'''.<ref>https://www.zx.net.nz/computers/ibm/psvaluepoint_425sxsi/</ref> This is the most common cap failure on PS/ValuePoint โ€” see [[IBM PS/ValuePoint Capacitor Replacement Guide]].
# '''Floppy drive logic board''' โ€” the Alps floppy drive used in many 6381-Fxx and similar boards has an SMD aluminium electrolytic capacitor next to the power connector that '''can leak'''.<ref name="sf08482">[https://www.zx.net.nz/computers/ibm/psvaluepoint_425sxsi/ zx.net.nz restoration notes &mdash; psvaluepoint 425sxsi]</ref> This is the most common cap failure on PS/ValuePoint โ€” see [[IBM PS/ValuePoint Capacitor Replacement Guide]].
# '''Planar electrolytics''' โ€” mostly through-hole; rarely fail; inspect for discolouration anyway.
# '''Planar electrolytics''' โ€” mostly through-hole; rarely fail; inspect for discolouration anyway.
# '''VLB / PCI slot connectors''' โ€” clean with eraser or contact cleaner. VLB slots have a high pin count and oxidise.
# '''VLB / PCI slot connectors''' โ€” clean with eraser or contact cleaner. VLB slots have a high pin count and oxidise.
# '''Video Frequency Controller chip''' โ€” located just left of the Tseng video chip. May be either '''ICS''' or '''Chrontel''' branded depending on production date. The OS/2 2.00.1 SVGA driver fails on Chrontel boards โ€” install the revised driver if you see this combination.<ref>http://ps-2.kev009.com/pcpartnerinfo/ctstips/e1f6.htm</ref>
# '''Video Frequency Controller chip''' โ€” located just left of the Tseng video chip. May be either '''ICS''' or '''Chrontel''' branded depending on production date. The OS/2 2.00.1 SVGA driver fails on Chrontel boards โ€” install the revised driver if you see this combination.<ref name="s094c49" />


== Regular Cleaning ==
== Regular Cleaning ==
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| +12 V || +11.4 V to +12.6 V
| +12 V || +11.4 V to +12.6 V
|-
|-
| &minus;5 V || &minus;4.75 V to &minus;5.25 V
| &minus;5 V || '''&minus;4.50 to &minus;5.50 V''' (&plusmn;10 %)
|-
|-
| &minus;12 V || &minus;11.4 V to &minus;12.6 V
| &minus;12 V || '''&minus;10.80 to &minus;13.20 V''' (&plusmn;10 %)
|}
|}
The two negative rails were previously given at &plusmn;5 %. Both the AT and the ATX specifications allow '''&plusmn;10 %''' on them, so a &minus;12 V rail at &minus;11.0 V is in specification and was being called a fault.<ref name="atxspec">Intel, ''ATX / ATX12V Power Supply Design Guide'', the specification these supplies are built to. It sets '''&plusmn;5 per cent''' on +3.3 V, +5 V, +12 V and +5 VSB, and '''&plusmn;10 per cent''' on &minus;5 V and &minus;12 V. The figures in this table are the specification's, not IBM's: IBM does not publish per-rail tolerances for these machines, and the supplies are bought-in industry-standard units.</ref> IBM publishes no per-rail tolerances of its own for these machines.


* '''6381-Si''' (100 W) โ€” sufficient for entry config; +12 V will sag if multiple drives added.
* '''6381-Si''' (100 W) โ€” sufficient for entry config; +12 V will sag if multiple drives added.
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* '''163''' โ€” Time and date not set.
* '''163''' โ€” Time and date not set.


After cell replacement, the '''F1 during memory count''' shortcut enters Setup. '''There is no Reference Diskette''' for PS/ValuePoint โ€” Setup is in ROM.<ref>http://ps-2.kev009.com/pcpartnerinfo/ctstips/e1f6.htm</ref>
After cell replacement, the '''F1 during memory count''' shortcut enters Setup. '''There is no Reference Diskette''' for PS/ValuePoint โ€” Setup is in ROM.<ref name="s094c49" />


=== External Battery Header ===
=== External Battery Header ===


The planar carries a '''J2 "External Battery" header''' and a '''JP8 "Battery Select" jumper'''.<ref>http://ps-2.kev009.com/pcpartnerinfo/ctstips/a26e.htm</ref> For long-term storage, fit a remote CR2032 holder on flying leads to J2 and move JP8 to "External" โ€” this lets you remove the planar's onboard cell without losing CMOS configuration during storage.
The planar carries a '''J2 "External Battery" header''' and a '''JP8 "Battery Select" jumper'''.<ref name="sd6b923">[http://ps-2.kev009.com/pcpartnerinfo/ctstips/a26e.htm kev009.com โ€” IBM PS/2 and PC document mirror &mdash; a26e]</ref> For long-term storage, fit a remote CR2032 holder on flying leads to J2 and move JP8 to "External" โ€” this lets you remove the planar's onboard cell without losing CMOS configuration during storage.


== Memory ==
== Memory ==
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== BIOS Update Procedure ==
== BIOS Update Procedure ==


All Type-2 boards (6382, 6384 VP2, 6387) share '''flash BIOS image L6JT70A.EXE (version 70)'''.<ref>http://ps-2.kev009.com/pcpartnerinfo/ctstips/ceda.htm</ref>
All Type-2 boards (6382, 6384 VP2, 6387) share '''flash BIOS image L6JT70A.EXE (version 70)'''.<ref name="s434595">[http://ps-2.kev009.com/pcpartnerinfo/ctstips/ceda.htm kev009.com โ€” IBM PS/2 and PC document mirror &mdash; ceda]</ref>


# Download the BIOS image from IBM's archive (or from a mirror such as the kev009 collection).
# Download the BIOS image from IBM's archive (or from a mirror such as the kev009 collection).
Line 158: Line 160:
* '''6384 P60/D''' โ€” VPP60FL6.EXE.
* '''6384 P60/D''' โ€” VPP60FL6.EXE.


'''BIOS v68 or later''' is required to enable '''P24T-83 Pentium OverDrive''' on 486 boards.<ref>http://ps-2.kev009.com/pcpartnerinfo/ctstips/859e.htm</ref>
'''BIOS v68 or later''' is required to enable '''P24T-83 Pentium OverDrive''' on 486 boards.<ref name="sb5cad8">[http://ps-2.kev009.com/pcpartnerinfo/ctstips/859e.htm kev009.com โ€” IBM PS/2 and PC document mirror &mdash; 859e]</ref>


== Cache Configuration ==
== Cache Configuration ==
Line 194: Line 196:


== References ==
== References ==
<references />
=== Further reading ===


* [http://ps-2.kev009.com/pccbbs/valuepnt/s61g1423.pdf IBM Hardware Maintenance Manual S61G-1423-01 (Sep 1993)]. Authoritative HMM for the 638x family.
* [http://ps-2.kev009.com/pccbbs/valuepnt/s61g1423.pdf IBM Hardware Maintenance Manual S61G-1423-01 (Sep 1993)]. Authoritative HMM for the 638x family.

Revision as of 22:20, 24 September 2026

This guide documents preventive maintenance for the IBM PS/ValuePoint family โ€” IBM's corporate / SMB ISA-based PC line from October 1992 to July 1995, machine types 6381 / 6382 / 6384 / 6387. Procedures are common to the family where possible; per-submodel procedures are called out where they differ.

Safety Warning

All PS/ValuePoint PSUs contain mains-rectified bulk capacitors that hold a lethal charge after power-off. Before any work inside the PSU shell:

  1. Power off and unplug the mains lead.
  2. Wait at least 30 seconds.
  3. Discharge the bulk capacitor through a 1 kฮฉ / 5 W resistor.
  4. Verify with a multimeter.

The PSU is universal-voltage on most submodels but uses a manual selector switch on the rear (115 V / 230 V). Verify the switch position before connecting mains โ€” IBM ships boards with the selector at 230 V from the factory, and powering a US 120 V mains into a board set to 230 V will not damage anything but the system will not power on; powering 240 V mains into a board set to 115 V will destroy the PSU.[1]

Identifying Your PS/ValuePoint

The machine type and submodel are printed on the rear-panel label (e.g. "Type 6381-Fxx", "Type 6384-1A3", "Type 6387-Yxx"). The MT maps to a Hardware Maintenance Manual (HMM):

  • IBM HMM S61G-1423-01 (September 1993) โ€” covers 6381, 6382 /S, 6384, 6384 /D, 6384 P60/D, 6387 /T.[2]
  • IBM HMM S61G-1423-02 (August 1996) โ€” updated HMM covering 638x and the later 64xx transitional machine types.[3]
  • IBM 6387/T Supplement S71G-1875-00 (May 1993) โ€” tower-specific supplement.[4]

Opening the System Unit

Tools: Philips #2 screwdriver, anti-static strap.

  1. Power off and unplug all cables (mains, keyboard, mouse, monitor, parallel, serial).
  2. Locate the cover screws on the rear panel.
  3. Loosen the screws. The cover slides off to the rear and lifts up.
  4. Inside:
    • Planar mounts horizontally on the chassis floor (desktop) or vertically (tower).
    • PSU is at the rear left.
    • Drive cage runs along the right side of the chassis (desktop) or top (tower).
    • ISA / VLB / PCI slots are on a riser card that plugs into the planar at right angles to the planar.

Cover Lock

Some PS/ValuePoints ship with a cover lock that requires a small key to open. Several systems were shipped from the factory without cover lock keys; if a system arrives with the lock present but no key, order a replacement cover lock assembly from IBM (or a modern locksmith can drill it out).[1]

Cover Switch / Interlock

Some PS/ValuePoint chassis carry a cover-interlock switch โ€” the system will not power on or power off if the cover is not seated properly.[1] If the system refuses to power on with the cover off, depress the cover-interlock pin manually with a screwdriver for a smoke-test.

Inspecting the Planar

Planar inspection items (in order):

  1. Lithium battery at B1 / BT1 โ€” verify the CR2032 cell is seated and shows no leakage. Replace if voltage is below 2.8 V.
  2. Floppy drive logic board โ€” the Alps floppy drive used in many 6381-Fxx and similar boards has an SMD aluminium electrolytic capacitor next to the power connector that can leak.[5] This is the most common cap failure on PS/ValuePoint โ€” see IBM PS/ValuePoint Capacitor Replacement Guide.
  3. Planar electrolytics โ€” mostly through-hole; rarely fail; inspect for discolouration anyway.
  4. VLB / PCI slot connectors โ€” clean with eraser or contact cleaner. VLB slots have a high pin count and oxidise.
  5. Video Frequency Controller chip โ€” located just left of the Tseng video chip. May be either ICS or Chrontel branded depending on production date. The OS/2 2.00.1 SVGA driver fails on Chrontel boards โ€” install the revised driver if you see this combination.[1]

Regular Cleaning

  • Soft brush and low-pressure compressed air for the planar, riser, ISA/VLB/PCI cards, drive bays and PSU vents.
  • Hold any fan blades by hand if using compressed air.
  • CPU heatsink (passive on 486SX-25 boards, fan-cooled on DX2/DX4 boards) โ€” clean fins; on DX4 or P60/D, replace original thermal compound at first service.
  • Clean ISA / VLB card edge fingers with a soft eraser or deoxidising contact cleaner.
  • Clean Mini-DIN-6 keyboard / mouse connectors with deoxidising contact cleaner on a foam swab.

PSU Voltage Checks

Probe the PSU output rails with a multimeter while the system is powered on (AT-style, not ATX).

Typical PS/ValuePoint PSU rail tolerances (AT-style)
Rail Acceptable range
+5 V +4.75 V to +5.25 V
+12 V +11.4 V to +12.6 V
−5 V −4.50 to −5.50 V (±10 %)
−12 V −10.80 to −13.20 V (±10 %)

The two negative rails were previously given at ±5 %. Both the AT and the ATX specifications allow ±10 % on them, so a −12 V rail at −11.0 V is in specification and was being called a fault.[6] IBM publishes no per-rail tolerances of its own for these machines.

  • 6381-Si (100 W) โ€” sufficient for entry config; +12 V will sag if multiple drives added.
  • 325T / original 6384 (145 W) โ€” design limit 10 W per slot.
  • 6382 /S, 6384 /D, P60/D, 6387 /T (200 W) โ€” universal voltage 90โ€“137 V LV / 180โ€“265 V HV.

Voltage Selector

The rear-panel voltage selector switch must be set correctly for your mains:

  • 115 V for 100โ€“127 V mains (US, Canada, Japan, etc.).
  • 230 V for 200โ€“240 V mains (UK, Europe, Australia, etc.).

IBM ships boards with the selector at 230 V from the factory. If you receive a North American unit and it does not power on, check this switch first.

Battery โ€” CR2032 Lithium Coin Cell

The PS/ValuePoint planar battery is a standard CR2032 lithium coin cell, not a soldered NiCd. Replacement procedure:

  1. Power off, unplug, discharge PSU.
  2. Locate the CR2032 in its snap-clip on the planar (typically labelled B1 or BT1).
  3. Pry the cell out with a fingernail or plastic spudger. Do not use a metal screwdriver โ€” shorting + and โˆ’ while levering can damage the planar power circuitry.
  4. Fit a fresh CR2032 with the + face up (matching the silkscreen).
  5. Power on; press F1 during memory count to enter Setup; re-enter date, time, boot order, drive parameters.

Symptoms of a dead battery (PS/ValuePoint inherits the classic IBM 161 / 162 / 163 POST cluster from the AT / PS/2 era):

  • 161 โ€” Battery dead / disconnected.
  • 162 โ€” CMOS checksum bad (configuration mismatch).
  • 163 โ€” Time and date not set.

After cell replacement, the F1 during memory count shortcut enters Setup. There is no Reference Diskette for PS/ValuePoint โ€” Setup is in ROM.[1]

External Battery Header

The planar carries a J2 "External Battery" header and a JP8 "Battery Select" jumper.[7] For long-term storage, fit a remote CR2032 holder on flying leads to J2 and move JP8 to "External" โ€” this lets you remove the planar's onboard cell without losing CMOS configuration during storage.

Memory

Memory varies dramatically by submodel:

  • 325T (386SLC) โ€” 72-pin parity SIMM, 70โ€“85 ns; 2 MB soldered + 2 sockets; 16 MB system max.
  • Original 1992 6384 (425SX, 433DX, 466DX2) โ€” 30-pin parity SIMM (the only PS/ValuePoint family with 30-pin), 70โ€“80 ns, installed in banks of 4, max 32 MB.
  • All other 6381 /Si, 6382 /S, 6384 /D, 6387 /T โ€” 72-pin parity SIMM, 70 ns (up to 85 ns), 4 sockets, max 64 MB.
  • 6384 P60/D โ€” 72-pin parity SIMM, 70 ns, installed in pairs for dual-channel, max 128 MB.

All PS/ValuePoint memory is parity. Do not fit non-parity SIMMs โ€” the POST will halt at a 2xx memory error.

Storage Maintenance

  • IDE drives โ€” clean drive connector. Original IBM drives (80 / 120 / 170 / 212 / 245 / 340 / 420 / 527 MB) are aged 25+ years and are unreliable; replace with CompactFlash-to-IDE or XT-IDE / IDE2SD adapter for long-term use.
  • Floppy drives โ€” Alps drives have the SMD electrolytic on the drive logic board that can leak. See IBM PS/ValuePoint Capacitor Replacement Guide. Replace head-cleaning belt if drive is intermittent.
  • Optional SCSI โ€” Future Domain 8-bit (TMC-850IBM) or 16-bit AT Fast SCSI adapter. Driver disks for DOS / OS/2 / Windows.

2.88 MB Floppy Support

  • 486 boards โ€” do not support 2.88 MB drives.
  • P60/D โ€” does support 2.88 MB drives.

Connector Care

  • Keyboard โ€” 5-pin AT DIN on most submodels (PS/2 Mini-DIN-6 on later /D boards).
  • Mouse โ€” PS/2 Mini-DIN-6 on planar.
  • Serial โ€” DB-9 male ร— 2 on most boards.
  • Parallel โ€” DB-25 female on planar.
  • Video โ€” 15-pin DSUB VGA on planar (Cirrus / Tseng / S3 / ATI Mach32 chip-dependent).
  • Cover lock โ€” IBM-keyed cylinder, OEM by Chicago Lock Company.

BIOS Update Procedure

All Type-2 boards (6382, 6384 VP2, 6387) share flash BIOS image L6JT70A.EXE (version 70).[8]

  1. Download the BIOS image from IBM's archive (or from a mirror such as the kev009 collection).
  2. Write to a write-protected DOS floppy. Critical: do not run the update from a Windows 95 / 98 / NT command prompt with the floppy unprotected โ€” the diskette can be corrupted by the OS.
  3. Boot from the DOS floppy.
  4. Run the BIOS update; do not power off until done.
  5. After update, re-enter Setup (F1 during memory count) and re-confirm boot order.

Per-MT BIOS images:

  • 6381 /Si โ€” L8JT52A.EXE.
  • 6382 /S, 6384 /D, 6387 /T โ€” L6JT70A.EXE (v70).
  • 6384 P60/D โ€” VPP60FL6.EXE.

BIOS v68 or later is required to enable P24T-83 Pentium OverDrive on 486 boards.[9]

Cache Configuration

L2 cache is field-upgradeable on most PS/ValuePoint 486 boards:

  • 6381 SX / DX โ€” supports 128 KB or 256 KB L2 cache module.
  • 6382 /S, 6384 /D, 6387 /T โ€” 128 KB or 256 KB L2.
  • Type 1 boards โ€” write-through L2.
  • Type 2 boards โ€” write-back L2.
  • 466DX2 โ€” 256 KB L2 standard.

If the L2 cache module is missing and a 12902 / 12904 POST code appears, fit an IBM cache module of the correct type.

  • Philips #2 screwdriver.
  • Anti-static strap.
  • Digital multimeter (DC and AC modes).
  • IPA + foam swabs.
  • Soldering iron with fine tip + solder wick (for floppy drive logic board recap).
  • Hot-air rework station (optional, useful for the floppy drive SMD cap).
  • Spare CR2032 cells.
  • DOS bootable floppy (or IDE-to-CF adapter with bootable DOS image).
  • DOS-formatted floppy + BIOS image for your specific MT.
  • IBM HMM PDF for your machine type.

References

  1. โ†‘ 1.0 1.1 1.2 1.3 1.4 kev009.com โ€” IBM PS/2 and PC document mirror — e1f6
  2. โ†‘ kev009.com โ€” IBM PS/2 and PC document mirror — s61g1423
  3. โ†‘ kev009.com โ€” IBM PS/2 and PC document mirror — S61G 1423 02
  4. โ†‘ kev009.com โ€” IBM PS/2 and PC document mirror — S71G 1875 00
  5. โ†‘ zx.net.nz restoration notes — psvaluepoint 425sxsi
  6. โ†‘ Intel, ATX / ATX12V Power Supply Design Guide, the specification these supplies are built to. It sets ±5 per cent on +3.3 V, +5 V, +12 V and +5 VSB, and ±10 per cent on −5 V and −12 V. The figures in this table are the specification's, not IBM's: IBM does not publish per-rail tolerances for these machines, and the supplies are bought-in industry-standard units.
  7. โ†‘ kev009.com โ€” IBM PS/2 and PC document mirror — a26e
  8. โ†‘ kev009.com โ€” IBM PS/2 and PC document mirror — ceda
  9. โ†‘ kev009.com โ€” IBM PS/2 and PC document mirror — 859e

Further reading