Iain
Member
Now I didn't initially intend obtaining any 286 computer, but in my quest for XT spares an IBM XT-286 system unit presented itself, and as it looked pretty much like a standard XT I thought I'd take the opportunity to acquire it. It contained a 5¼" floppy disk, a 30Mb hard disk and a video card, so seemed to justify itself in spares value alone.
However, before I'd even got my hands on the unit a little research reminded me of some significant differences that I had not stopped to consider. The board layout is quite different, it uses a 16-bit bus and it has a battery-backed BIOS. There was also the matter of it being just a system unit on its own, so not only no keyboard or monitor, but this meant that there was no way of knowing its working condition.
Anyway, once I had the unit I opened it up and checked the video card. It was an MDA type, so I connected up a suitable monchrome monitor, then added a keyboard and powered it up. There was a good deal of humming and whirring from the power supply, then some response from the monitor - but no activity from the disk drives.
The monitor just showed a cryptic "000000 0002 202", and that was it. Repeated switching off and back on resulted in the same response.
I then decided to have another check of the system. A closer look suggested that it has suffered from neglect for some time. As the XT-286 is actually an AT it has a battery-backed up CMOS. A quick examination of the battery compartment confirmed that this computer has not had much tender loving care. The contents of the old 6-volt battery was seeping out of its container.
Unlike the older XT's with their BIOS in ROM the demise of the XT-286's battery meant that the BIOS settings had disappeared. Hence there was not likely to be any disk activity. Unfortunately, a replacement battery failed to alter any of the above symptoms.
This left me with some questions to ponder:
1. Should I have seen some BIOS information come up on the screen as soon as I applied power?.
2. Would a fault with the graphic card prevent the BIOS info appearing but allow that single line of numbers to appear?
3. Does that numeric sequence ("000000 0002 202") have any diagnostic relevance?
4. Would a memory fault prevent the BIOS info appearing?
If anyone has come across anything similar I'd be interested to hear your suggestions.
However, before I'd even got my hands on the unit a little research reminded me of some significant differences that I had not stopped to consider. The board layout is quite different, it uses a 16-bit bus and it has a battery-backed BIOS. There was also the matter of it being just a system unit on its own, so not only no keyboard or monitor, but this meant that there was no way of knowing its working condition.
Anyway, once I had the unit I opened it up and checked the video card. It was an MDA type, so I connected up a suitable monchrome monitor, then added a keyboard and powered it up. There was a good deal of humming and whirring from the power supply, then some response from the monitor - but no activity from the disk drives.
The monitor just showed a cryptic "000000 0002 202", and that was it. Repeated switching off and back on resulted in the same response.
I then decided to have another check of the system. A closer look suggested that it has suffered from neglect for some time. As the XT-286 is actually an AT it has a battery-backed up CMOS. A quick examination of the battery compartment confirmed that this computer has not had much tender loving care. The contents of the old 6-volt battery was seeping out of its container.
Unlike the older XT's with their BIOS in ROM the demise of the XT-286's battery meant that the BIOS settings had disappeared. Hence there was not likely to be any disk activity. Unfortunately, a replacement battery failed to alter any of the above symptoms.
This left me with some questions to ponder:
1. Should I have seen some BIOS information come up on the screen as soon as I applied power?.
2. Would a fault with the graphic card prevent the BIOS info appearing but allow that single line of numbers to appear?
3. Does that numeric sequence ("000000 0002 202") have any diagnostic relevance?
4. Would a memory fault prevent the BIOS info appearing?
If anyone has come across anything similar I'd be interested to hear your suggestions.