IBM PS/2 Model 30 Troubleshooting Guide - Revision history

Josh: Add representative photo (Wikimedia Commons, attributed on file page)

2026-07-16T12:06:57Z

Add representative photo (Wikimedia Commons, attributed on file page)

← Older revision		Revision as of 13:06, 16 July 2026
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			[[File:IBM PS-2 Model 30 (photo).jpg\|thumb\|right\|300px\|IBM PS/2 Model 30. Source: Wikimedia Commons.]]
	This guide covers diagnostic procedures and the complete IBM PS/2 numeric POST error code reference applicable to the '''[[IBM PS/2 Model 30]]''' (machine type 8530 — Model 30 8086 and Model 30 286). The Model 30 uses the same PS/2 BIOS POST architecture as the rest of the PS/2 line, sharing audio beep codes and Major/Minor numeric error codes with the [[IBM PS/2 Model 25 Troubleshooting Guide\|Model 25]]. This guide focuses on faults specific to the Model 30 (ISA-bus, proprietary ST-506 HDD, MCGA / VGA distinction).		This guide covers diagnostic procedures and the complete IBM PS/2 numeric POST error code reference applicable to the '''[[IBM PS/2 Model 30]]''' (machine type 8530 — Model 30 8086 and Model 30 286). The Model 30 uses the same PS/2 BIOS POST architecture as the rest of the PS/2 line, sharing audio beep codes and Major/Minor numeric error codes with the [[IBM PS/2 Model 25 Troubleshooting Guide\|Model 25]]. This guide focuses on faults specific to the Model 30 (ISA-bus, proprietary ST-506 HDD, MCGA / VGA distinction).

Josh: Expand troubleshooting: RIFA/tantalum + Dallas/planar battery (161/163) + POST codes; cited

2026-07-15T23:16:59Z

Expand troubleshooting: RIFA/tantalum + Dallas/planar battery (161/163) + POST codes; cited

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 * '''Random crashes under load''' &mdash; aged PSU electrolytics. Recap.
 * '''VGA shows wrong colours (Model 30 286)''' &mdash; planar VGA gate array (15F6864) failing.
 == Related Pages ==

Josh: Create comprehensive IBM PS/2 Model 30 / Model 50-60 / Model 70-80 page set with full PS/2 POST code reference, MCA architecture detail, capacitor lists, ECA recalls, and SMD electrolyte leakage diagnosis per RTC style guide

2026-05-21T21:59:09Z

Create comprehensive IBM PS/2 Model 30 / Model 50-60 / Model 70-80 page set with full PS/2 POST code reference, MCA architecture detail, capacitor lists, ECA recalls, and SMD electrolyte leakage diagnosis per RTC style guide

New page

This guide covers diagnostic procedures and the complete IBM PS/2 numeric POST error code reference applicable to the '''[[IBM PS/2 Model 30]]''' (machine type 8530 — Model 30 8086 and Model 30 286). The Model 30 uses the same PS/2 BIOS POST architecture as the rest of the PS/2 line, sharing audio beep codes and Major/Minor numeric error codes with the [[IBM PS/2 Model 25 Troubleshooting Guide|Model 25]]. This guide focuses on faults specific to the Model 30 (ISA-bus, proprietary ST-506 HDD, MCGA / VGA distinction).

== Audio Beep Codes ==

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Model 30 power-on audio codes'''
! Pattern !! Meaning
|-
| 1 short || POST OK
|-
| 2 short || Numeric error displayed; read screen
|-
| 1 long + 1 short || Display or display adapter problem (MCGA / VGA)
|-
| 1 long + 2 short || Display or display adapter problem (VGA)
|-
| 1 long + 3 short || EGA / display adapter problem
|-
| Continuous short beeps || Keyboard problem — check fuse, cable, 8042 controller
|-
| Continuous solid beep || System board failure
|-
| Click then no beep || PSU started but Power Good not asserted in 150 ms — suspect shorted tantalum
|-
| No display and no sound || PSU fold-back protection, shorted planar capacitor, or PSU dead
|}

== Numeric POST Error Codes ==

The Model 30 uses the standard PS/2 numeric error format. Codes specific to the MCA subsystem (which the Model 30 does not have) are absent — the Model 30 only triggers the ISA-class codes (1xx through 24xx in the main range, plus 86xx for the pointing device).

=== 1xx — System Board ===

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Major code 1xx — system board'''
! Code !! Meaning
|-
| 101 || Interrupt failure / processor error
|-
| 102 || Timer 0 failure or BIOS ROM checksum error — reseat the ROM if socketed
|-
| 103 || Timer interrupt failure
|-
| 104 || 8259A controller error (Model 30); protected mode failure (Model 30 286)
|-
| 105 || Last 8042 keyboard controller command not accepted
|-
| 106 || Converting logic test (planar)
|-
| 107 || NMI test failure
|-
| 108 || Timer bus test failure
|-
| 109 || DMA (8237A) test error
|-
| 110 || Planar parity error
|-
| 111 || I/O parity error
|-
| 121 || Unexpected hardware interrupt
|-
| 151 || Bad battery (Model 30 286 only)
|-
| 152 || CMOS error / power-on password installed
|-
| 161 || CMOS configuration empty — '''Model 30 286: replace battery'''
|-
| 162 || CMOS checksum mismatch — run SETUP from Reference Diskette
|-
| 163 || Time and date not set
|-
| 164 || Memory size error — run SETUP
|-
| 199 || User-indicated configuration not correct
|}

==== Model 30 286 161 / 162 / 163 cluster ====

This cluster on a Model 30 286 indicates a dead Dallas DS1287 / DS12887 RTC battery. Replace per [[IBM PS/2 Model 30 Maintenance Guide]] and re-run SETUP.

The Model 30 8086 does '''not''' report 161 / 162 / 163 because it has no hardware RTC.

=== 2xx — Memory ===

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Major code 2xx — memory'''
! Code !! Meaning
|-
| 201 || Memory test failed — data miscompare or parity error
|-
| 202 || Address line 0–15 failure
|-
| 203 || Address line 16–23 failure (Model 30 286 only)
|-
| 207 || ROM failure
|-
| 211 || Base 64 K on I/O channel failed
|-
| 215 / 216 || Base 64 K on daughter card failed
|-
| 225 || Wrong / defective / slow memory
|}

The Model 30 8086 has 640 KB on planar; the failing bank cannot be in expansion (there is no expansion bank). A 201 error therefore identifies the failing chip on the planar by bit pattern. The Model 30 286 has two MMK SIMM sockets, and the failing bank is identified by the leading hex digits of the 201 code.

=== 3xx — Keyboard ===

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Major code 3xx — keyboard'''
! Code !! Meaning
|-
| 301 || Keyboard did not respond / stuck key. The XX value preceding "301" is the scan code of the stuck key. Also occurs if keyboard plugged into mouse port
|-
| 302 || User-indicated keyboard test failure
|-
| 303 || Keyboard or 8042 controller error
|-
| 304 || Planar (8042) error / CMOS does not match keyboard
|-
| 305 || +5 V fuse blown on planar (3 A) — replace fuse and inspect keyboard / mouse for shorted cable
|}

==== 301 with X-scan-code ====

If the Model 30 reports "XX 301" at POST and the XX is a hex scan code, an object resting on a key is the most likely cause. If multiple keys appear stuck, also see 8602. On the Model 25 / Model 30 family, the keyboard and mouse ports are interchangeable at the 8042; plugging a mouse into the keyboard port (or vice versa) raises a 301 + 8603 pair.

=== 4xx — Monochrome / MCGA display ===

* 401 — MCGA / monochrome adapter test failure (planar VGA on Model 30 286 also raises 4xx on certain error paths).

=== 5xx — Colour / MCGA / VGA ===

* 501 — CGA / MCGA / VGA colour test failure.

=== 6xx — Diskette ===

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Major code 6xx — diskette'''
! Code !! Meaning
|-
| 601 || Drive or controller test failed
|-
| 602 || Boot record on diskette invalid
|-
| 606 || Verify function failed
|-
| 607 || Diskette write-protected
|-
| 610 || Initialisation failed
|-
| 611 || Timeout
|-
| 612 || Bad NEC FDC status
|-
| 613 || Bad DMA
|-
| 621–626 || Seek / CRC / address mark / record / data compare failures
|-
| 650 || Drive speed error
|-
| 651–656 || Format / verify / read / write / controller / drive failures
|-
| 657–660 || Write-protect or change-line signal stuck
|}

The Model 30 with the proprietary ST-506 hard disk reports 6xx codes only for the floppy. 17xx codes cover the hard disk.

=== 7xx — Math coprocessor ===

* 7xx — 8087 (Model 30 8086) or 80287 (Model 30 286) math coprocessor error. The 80286 BIOS does not test the 80287 unless software invokes it.

=== 9xx / 10xx — Parallel port ===

Same code structure as PC/AT and Model 25.

=== 11xx / 12xx — Serial port ===

Same code structure as PC/AT and Model 25.

=== 17xx — Fixed disk ===

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Major code 17xx — fixed disk'''
! Code !! Meaning
|-
| 1701 || Controller POST error
|-
| 1702 || Controller timeout
|-
| 1703 || Seek failure
|-
| 1704 || Adapter or drive error
|-
| 1780 || Drive 0 timeout at IPL
|-
| 1781 || Drive 1 timeout at IPL
|-
| 1790 / 1791 || Format not recognised / data cable off
|}

On the Model 30 8086 with the famously failure-prone ST-506 drive, 1701 / 1780 with the drive present is most commonly drive stiction or drive failure. Gentle rotation of the drive case (powered off) may free a stuck spindle for one boot; replace the drive at the earliest opportunity.

=== 24xx — Integrated VGA (Model 30 286) ===

* 2401 — Planar VGA error.
* 2402 — Diagnostic video error.
* 2408 — VGA ground circuit fault.

=== 86xx — Pointing device ===

* 8601 / 8603 / 8604 — planar (8042) or pointing-device error. Most commonly a mouse plugged into the keyboard port.

== Reference Diskette and Advanced Diagnostics ==

The Model 30 8086 and the Model 30 286 use '''different''' Reference Diskettes. Always cold-boot the Reference Diskette (insert before powering on) — warm-booting may report false errors. From the main menu, '''Ctrl-A''' enters Advanced Diagnostics which produces minor (NN) codes giving further FRU-level detail.

The Reference Diskette is also where SETUP is performed; the Model 30 BIOS has no built-in setup screen.

== Dead System Isolation ==

If the Model 30 shows no signs of life:

# Verify the wall outlet and mains lead.
# Open the system unit.
# Verify the PSU output rails at the planar power connector with a multimeter (+5 V, +12 V, −5 V, −12 V).
# If rails are absent, suspect the PSU. The Model 55 PSU is a drop-in replacement.
# If rails are present but the system is dead, remove all ISA cards and the optional hard drive.
# Power on with planar, riser and (Model 30 286) one SIMM only. Listen for a beep.
# If no beep, suspect bank-0 memory on planar (Model 30 8086 has integrated DRAM — suspect the DRAM chips at U-positions on the planar) or the SIMM (Model 30 286).
# Re-add cards one at a time until the failing card is identified.

The PS/2 PSU asserts Power Good within 150 ms or shuts down internally. A shorted tantalum on the planar can pull the PSU into fold-back protection and produce a "click then nothing" symptom.

== Common Symptoms ==

* '''Continuous beep, no display''' — shorted tantalum or keyboard fuse blown.
* '''161 / 162 / 163 cluster at every boot (Model 30 286)''' — dead Dallas RTC battery.
* '''Drive does not detect any diskette''' — PS/2 single-cable connector seated badly, or drive logic-board capacitor leak.
* '''ST-506 hard drive not detected''' — drive failure (very common on the original ST-506 fitted to 8530-021 / E21 / E31).
* '''Random crashes under load''' — aged PSU electrolytics. Recap.
* '''VGA shows wrong colours (Model 30 286)''' — planar VGA gate array (15F6864) failing.

== Related Pages ==

* [[IBM PS/2 Model 30]]
* [[IBM PS/2 Model 30 Maintenance Guide]]
* [[IBM PS/2 Model 30 Capacitor Replacement Guide]]
* [[IBM PS/2 Model 25 Troubleshooting Guide]] — sister all-in-one
* [[Capacitor Failure Symptoms]]

== References ==

* [https://www.ardent-tool.com/trouble/ps2error.html PS/2 Error Codes], Ardent Tool of Capitalism. Authoritative source for the complete 1xx–25xx PS/2 numeric error code listing, the Power-Good-in-150-ms PSU spec, and dead-system isolation procedure.
* [http://museodelcomputer.org/parts/ibm/ps2_50z/docs/error_codes.htm PS/2 Error Codes], Museodelcomputer.org. Reference for the audio code patterns and minor code structure.
* [https://www.dosdays.co.uk/computers/IBM%20PS2%20Model%2030/ibm_ps2_model_30.php IBM PS/2 Model 30 — DOS Days]. Reference for the proprietary ST-506 interface, ISA-bus expansion, MCGA / VGA distinction and the (failure-prone) original hard drive.
* IBM, ''IBM Personal System/2 Hardware Maintenance Manual'' (S30G-2207, October 1994). FRU listings and error-code references.
* IBM, ''IBM Personal System/2 Model 30 Reference Diskette''. Source for SETUP, Advanced Diagnostics (Ctrl-A).

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