First post, by computerguy08
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I've recently got this 286 board from the flea market, yet another one of those Suntac 286 boards, of which Predator99 has one in this thread: Suntac 80286 Mainboards
http://www.win3x.org/uh19/motherboard/show/955
As usual, it came packed with a Varta killer, which ate away some of the traces near the keyboard controller. After some careful soldering, I patched the broken traces in that area and replaced the corroded parts with new ones.
Unfortunately, the board does not show any signs of life, no beeps, no POST codes. Sometimes, the IRDY led lights up on the POST card , sometimes not.
On the scope, I can see some activity on the CPU address lines, but not on the data lines (I see activity there when the IRDY led is on).
Other things I tried so far:
- Landmark Supersoft: no beep codes
- other BIOS images: again, no beeps
- reflowed and cleaned the CPU socket
Right now, I'm stuck in the diagnostic process, not sure what should I try next to make it show any sign of life.
Is there a clock signal generated in the RTC area (where the battery leaked) which is required for the CPU to run code from the ROM or something ?
If anyone has experience with these Suntac boards (or other early 286 boards), some advice would be appreciated.
P.S: if anyone is interested, I dumped the BIOS images and uploaded them in the UH19 page of this board (link above).
