View Full Version : 286 Woes - What To Look For?

October 26th, 2016, 08:20 AM
My 286 PC hadnt been turned on for about a month. Upon turning it on again it boots up fine, loads the RAM / loads DOS. But after about 5-8 minutes or so it becomes completely unresponsive and just sits at whatever prompt it was last on. The Monitor doesnt go off, it doesnt shut down or beep, just sits there. The keyboard lights stays on (the numlock key) and pressing it does nothing as does pressing any keys.

If you power it off and then turn it back on, you can hear it start to post, and boot, but no video comes on screen and the PC wont go any further. However, if you wait a good 30-45 min and turn it on, it will boot up but go through the process I mentioned at the start of this post.

Could something be overheating possibly? Something come loose?

Just looking for some advice on where to start looking....

October 26th, 2016, 08:35 AM
Where I'd start would be re-seating all of the socketed ICs in the unit. Even slight corrosion or oxidation can lead to strange problems.

October 26th, 2016, 08:41 AM
It does seem like something thermal, but a 286 doesn't normally just overheat.

There is a good chance it is just a loose memory chip or ISA card. It could also be a bad solder connection somewhere.

You will need to disassemble and inspect the entire thing. Carefully re-seat any socketed chips, clean off any dust, and check any fans to make sure they are running. Also test with any non-critical cards removed.

If that still doesn't help, inspect the motherboard and cards with a magnifying glass for any obvious solder problems or other damage.

If you are lucky, it is just something loose. Although chips can fail internally like that where they become intermittent or fail only when warm. If that is the case you may be able to narrow it down by using compressed air or something to cool specific chips while testing.

I used to have a cheap 386sx motherboard sort of like that, where it would run fine for a few minutes and then freeze unless it was taken off of "turbo". Narrowed it down to the CPU as keeping it cold would let it run longer, but since that CPU was soldered on to the board, there was nothing that could be done about it.

October 26th, 2016, 10:16 AM
Thanks for the ideas....gonna open it up this weekend and see what I can find....will report the results

October 31st, 2016, 09:41 AM
Thanks for the assistance guys...it must have been loose ram on the RAM card that was installed on the computer as pushing them all in / reseating all the cards got the machine back up and running properly.

Much appreciated!!