The "Known-Problem" Page

This page contains some problems, which are already welknown in the technicians field - but have not reached the public yet. Or have not reached those people which operate with PS/2 for the first time or only recently.
Here are some "Known Problems" - and how to solve them.

Error 10483: Seagate ST-177I doesn't spin at Power On (55SX / 70)
Time / Date / Config lost / Disk Error on Mod. 60/80
24 MB RAM installed - only 16 MB available (55SX,56,57...)
Unit does not run with cover removed (9556/57 9576/77)
Can access harddisk only with boot-disk (various models)
Installed Non-IBM SCSI CD-ROM under DOS and cannot access it
Misleading error-Code 0002 11CZ on Mod. 9556 / 9557
What's that "Key Symbol" I get after starting the machine ?
Screen stays black after going from Win95 to DOS

(Is to be continued recently)

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No. 1: Error 10483: Seagate ST-177I doesn't spin at Power On (55SX / 70)
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The Seagate ST-177I 60MB harddisk used on many Mod. 55SX (8555-061) and on some Mod. 70 (70-061) tends to hang at Power On.
This effect appears sometimes after the computer was off for a longer time. It is a result of adhesive-power between disk surfaces and r/w-heads. The surfaces are very plain polished and the heads really 'suck' on them. The spindle motor has not enough torque to loosen the platters from the heads.

There's no 'soft' solution.
Several Power On cycles (20 sec. On, then 20 sec. Off) may start the drive ... or blow up the power-supply. And is no good treatment for the electronic components at all.

Alternatively: Unplug the system-unit from everything, shake it (up/down several times) then rotate the unit with a sharp kink clockwise some times. Plug it on again and Power on. The heads should have released and the drive spins up.

Don't lift the unit up on the frontside and let it crash back on the desk.
This method will definitely kill your harddisk very soon.

In either case you have badly treated your Harddisk and it is a good idea to begin backing up the data ... !

I have had good success with putting the system-unit on the rear seat of my car and drive to town, let the car on a sunny parking lot, go shopping, come back, drive home and plug it back on. Afterwards the drive runs again.
Changes of temperature and the vibrations have caused the heads to release from the disk surfaces.

Disadvantage: my friend tried the same with his Mod. 55. Some guys broke his car open and stole the computer.

No. 2: Time / Date / Config lost / Disk Error on Mod. 60/80
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Believe it or not: the above mentioned errors often have one common reason. Most recent effect is a frequent lost of configuration, internal clock shows totally wrong values after longer power off cycles or the disk drive has a lot read/write errors and installing a new battery or cleaning the disk-drive doesn't help.

Of course: it is a cleaning problem, but on the systemboard.
The area on the systemboard just under the power supply fan tends to get very dirty during the years. It is a good idea to fully disassemble the computer and blow through the power supply with a compressor and a fine nozzle.

Don't do this in your office !

Everything will get very dirty. It is astonishing how much dust can sit inside a single power supply.

Now look on your systemboard. It is awfully dirty, right ? I thought so. Take a brush and a vacuum-cleaner to get it properly clean. Look for dust and particles, which stuck between pins of the integrated circuits.

Just under the area where the fan sits, you will find (on a Mod. 80 board - after a close look)

  • the 8042 systemboard controller - for i.e. the keyboard
  • the MC146818A CMOS configuration storage and RTC
  • the D7205 disk-drive controller
  • the NS16550 serial interface controller
  • a 32.768 KHz crystal for the RTC
  • (sometimes) the 8259A Interrupt controller ...

All in all this is a very sensible area - and the collected dust is conductive in most cases and may cause the above mentioned trouble. Re-assemble the PC, start reference disk, set date, time and configuration again and try, if everything works again.

No. 3: 24 MB RAM installed - only 16 MB available (55SX / 56 / 57 ...)
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In a brief: you cannot install more than 16 MB on machines with a 386SX-processor.

"Oh - sure, but my 9556 has a 486 !"
"Really ? Wasn't it a 486-SLC ?"
"Uhm ... er, yes ... think so !"

Gotcha. The 486-SLC is a Turbo-386SX. Ever wondered why they offer just a 387SX as mathematical Co-processor ? Now - that's the reason. The 486-SLC family has the internal 1st-Level-Cache like a 486 and some of the newer instructions, technically they are a 386SX. And these have only a 16-bit databus and 24-bit adressbus externally and can only adress 16 MegaByte.
24 adress-lines = 2 ^ 24 bytes adress-space= 16.777.216 bytes
They are from the technicians point of view similar to the 286-processor, but can internally operate with 32-bits and 32-bit specific programs will run on them. They can even carry out 32-bit busmaster functions, unless they have only 16-bit MCA connectors (the short ones).

But the adress-space is limited to 16MB due to the lack of adressing lines.

Sad but true.

No. 4: Unit does not run with cover removed (9556/57 9576/77)
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Certain Premium Line models 9556, 9557, 9576 and 9577 do not run with the cover removed.

This comes, because they have a security-switch built into the front of the base unit, which interrupts the power-supply. This little switch is easy to find - it is blue and sits somewhere left from the disk-drive bay.
It can be pushed with the finger gently upwards and to the inside - and the machine runs fine without the case.

No need to be afraid: both - the power-switch as well as the security switch - operate at low voltage. They switch only a +5V sense-line, not mains voltage.

But watch out: sometimes the security switch flips back after some time or when accidently bumping against the system.
Result: the machine switches off immediately again. This is pretty annoying, when having just 95 percent from a software installed ...

The same switch is sometimes defective, after rude, careless people violently push the case over the machine - or stuff the machine into the cover respectively. It breaks and the machine won't power on.
If you are experiencing a machine, which does not power on, inspect this switch first, before you begin replacing parts like systemboard or power-supply.

No. 5: Can access harddisk only with boot-disk (various models)
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Various machines -namely Premium Lines 95xx- have something called 'Selectable Boot-Sequence'.
This is a setup for the order the bootable devices are tracked down for an operating system.

Valid boot-devices are

  • Disk-Drive(s)
  • Harddisk(s)
  • CD-ROM drive
  • Network Adapter supporting RPL (Remote Program Load)

In case the first harddisk unit is missing in this device-list -by what reason- there will be no boot from it. It can however been accesses with using a boot-disk in drive A:.

In case there is a valid IML-track on the first harddisk (on those machines supporting IML-track), a valid operating system installed and the first partition is set active to be bootable and the machine still refuses to boot from harddisk, check in the reference under 'Features' / 'Boot Sequence' if the harddisk is in the list of bootable devices.
If not - select it and try again.

In most cases it will work then.

No. 6: Installed Non-IBM SCSI CD-ROM under DOS and cannot access it
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Assumed, you installed an IBM SCSI-Adapter or used the one in your machine (card or onboard) to connect a SCSI CD-ROM drive to it. The adapter is recognized in the setup and so is the CD-ROM drive. But you cannot access it. What's wrong ?

Do the following:

  • get the SCSI CD-ROM Driver Disk SCSICDRM.EXE from IBM ftp
  • extract it to a 720K / 3.5" disk
  • run the UINSTALL-program from the disk to install the device-driver IBMCDROM.SYS
  • use a Text-Editor to add /i in your CONFIG.SYS at the end of the line with the IBMCDROM.SYS
  • If you have a CD-ROM (like some NEC) and it refuses to work even after adding the /i try to add a /P:2 as well to enable the read seek command on this unit too. (Thanks White Box !)
  • restart the system

This little /i will convince the IBMCDROM.SYS to accept all CD-ROM drives, which do not have the !x-sign in their device descriptor and therefore are recognized as Non-IBM devices.
Works fine with NEC, Toshiba, Panasonic, Sony etc.
BTW.: It pays to read the README-file on the SCSICDRM-disk ...

Pretty easy, right ?

No. 7: Misleading error-Code 0002 11CZ on Mod. 9556 / 9557
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Sometimes problems are reported with the appearance of the Error code 0002 11CZ on the PS/2 Models 9556 and 9557. The 2xx-codes basically point in the direction of defective memory. In fact this failure is mostly caused by a missing / invalid memory module installed in the machine.
Remind that this machines accept Parity memory only (suffix -P- or -36- on the module sticker), which must match the IBM Presence Detection scheme and should have 70ns access-speed. In case there is a memory module installed, which does not supply presence detection the error 0002 11CZ shows up - like as if there were no module installed at all.

The 211-error (0002 11xx is only the extended 8-digit output on the later Premium Line machines) means basically:
211 Check Memory with the device path to track
  1. processor board (Mod. 90 / 95)
  2. systemboard memory
  3. memory riser cards (Mod. 90 only)
  4. system board

No. 8: What's that "Key Symbol" I get after starting the machine ?
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The little "Key Symbol" indicates that the machine has a "Power On Password" (POP) set.

How to delete this password ?

Mod. 8525 / 8530 (286-CPU)Jumper J13
Mod. 8525 (386-SX)Jumper J2
Mod. 8530 / 8540Jumper J14
Mod. 8550 / 8560 / 8570 / 8580Jumper or cable at Speaker/Battery unit 1)
Mod. 8555 / 8565 (386-SX)Speaker Cable at Sysboard 2)
Mod. 8556 / 8557Jumper J18
Mod. 8573 (P70 and P75)Jumper close to MEM4 (proceded as with 1) )
Mod. 8590Jumper J10
Mod. 9533, 9535/9540Jumper J20
Mod. 9556 / 9557Jumper JMP1 - Do not touch JMP2 ! 3)
Mod. 9576 / 9577Jumper JMP1 - Do not touch JMP2 ! 3)
Mod. 9595 (Server 95)Jumper JMP1 - Do not touch JMP2 ! 3)
Mod. 9585 (Server 85)Jumper J16

Usually the systems have a 3-pin jumper. To erase the POP toggle the jumper - cover mid-pin and the one currently not used. Leave the jumper in that position until the password needs to be erased next time.

Note 1
Locate the Speaker/Battery unit. The older version of that unit has a 2-pin jumper at the left side - apply a short between the two pins and power the machine on. Remove the short after the memory count finished and the machine beeped.
Later models have a short thin black cable with an insulated connector at the end hanging around on the unit. Use a piece of wire or a meter lead to short to GND (power supply case, FDD, HD-Subframe etc.). Also power on the machine and release the short after memory test completed and machine beeped.

Note 2
Locate the cable from the systemboard to the speaker unit. Detach the cable at the systemboard, turn it over by 180 degrees and plug it back into the systemboard connector. Then power on the machine - password deleted. Leave the cable that way until you need to erase the password next time ...

Note 3
The JMP2 enables / disabled the "Priviledge Access Password" (PAP). Default is "PAP disabled". On various machines the PAP fulfills C2-Security regulations and cannot be deleted except through entering the PAP again. Once you'd accidently set a PAP and forget it - the systemboard must be replaced ...
Therefore: hands off from this jumper !

No. 9: Why stays my screen black when I leave Win95 into DOS ?
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A very common mishap is that: you click the "Start" bottom / left and select "End", then select "Start MS-DOS" from Win95. Next you sit in front of a machine with a totally blanked screen.
Is the machine dead ? No - it isn't. Toggling NumLock alters the state of the NumLock LED, so the machine is still working. But the screen shows no prompt. Reboot works too.

To ressolve this you might blindly type mode co80 - which returns a screen with the DOS-prompt.

Now - agreed - this is only a very unsatifying solution. You can do this automatically.
Create a DOSSTART.BAT in the C:/WINDOWS directory. It contains only one line:

mode co80

This file is started any time you leave Win95 to MS-DOS - all command lines in this DOSSTART.BAT are executed when starting up the DOS. This is also the place to put keyboard-drivers to. Or probably a scanner-driver or GUEST.EXE for an IOMEGA ZIP-drive ... everything you would normally start within an AUTOEXEC.BAT when you have a DOS-only machine.
However: "Real Mode" device drivers like for a CD-ROM or scanner-drivers that needs to be placed in the CONFIG.SYS cannot be put here. They will have to be installed in the CONFIG.SYS too.
But careful: a too old driver may crash Win95 or force it to run in 16-bit compatibility mode.

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© 1997 by Peter H. Wendt / pw-software production