First post, by DonutKing
- Rank
- Oldbie
I have recently acquired a 286 motherboard. It's a Chaintech ELT-286B-1000-SM. Here is a photo. Please note that all the photos in this post are about 2MB so I've linked them instead of embedding them.
It's got a 10MHz AMD PLCC CPU, which gets surprisingly hot during operation.
The BIOS Options are very basic- that's all there is in that pic, no extra pages of settings.
I can't find anything about it on the internet, and none of the jumper settings or panel connections are labelled. Here is a shot of the jumpers/panel connectors.
On the top left, J18 i'm not sure about, J19 is speaker. J25 I think might be wait states for memory? I'm only assuming that since its so close to the memory banks. I tried switching it and got no discernable difference. J26 and J30 I have no idea about. J3 and J4 on the upper right set the installed memory size, experimenting with that gives 512KB, 640KB and 1MB memory (and also a no-boot on one of the settings).
The only other jumper is on the opposite end of the board and is the color/mono jumper. These are only applicable to CGA cards right?
If someone could provide further info on this board and its settings I'd appreciate it:) I've looked through TH99 but have been unable to locate it.
Also, this board has some issues. It seems to work ok for a while but then it eventually starts rebooting itself. Often it will cut all the text in half horizontally for a few seconds before a cold reboot; sometimes it hangs at the VGA BIOS or POST screen. I've tried 3 different VGA cards and they all do this. I notice in the BIOS it only has options for EGA and not VGA but I didn't think this would be the issue.
At first I thought it was heat related since it seems to only happen after prolonged use, and it comes good for a while if you let it sit before starting it again. If you just reboot straight away it will continue to crash. The little CPU heatsink gets surprisingly warm so I pointed a fan at it and this seemed to help stabilise it for a while but it didn't fix it completely. The heatsink is cool to the touch with fan now. Some of the other IC's get warm but I wouldn't say they were 'hot' like the CPU.
I've tried the following to try to fix it:
-Removed barrel battery and cleaned up some minor corrosion. Visually nothing seems to have been eaten away.
-Reseated all DIP RAM.
-Reseated all removable IC's including CPU, cleaned contacts with electronic cleaner.
-inspected for corrosion or cold solder joints, can't see any.
-Tried limiting RAM to 512
The board seems to have a number of yellow tantalum capacitors, mainly 10uF. Do tantalum caps go bad with age? Is it worth replacing them?
Since these things aren't being made any more I'd hate to have to throw it away. So any advice you can offer to make it work again would be appreciated 😀