Hi guys,

I've been working on 20 or more 286-486 motherboards I picked up in a lot, and I have repaired all but a few.

I would really like to get this biostar mb-8433uud-a up and running, because it has a lot of nice features and support., and is likely the best of the bunch. This one is in immaculate condition with no apparent damage to traces, memory slots, no bulging capacitors, etc. Came setup with an AMD x586-P75, which ran fine at 160 MHz in another board. 80 ns RAM is also known working, but it acts the same even without RAM.

The Biostar board: https://www.win3x.org/uh19/motherboards/1075

Post codes 00 and C1 come up immediately at power up (all post card LEDs lit appropriately):

C1 is "Memory size checked", and perhaps it's getting stuck at this one?

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I cleared the CMOS at JP12.

I have flashed the latest BIOS that Feipoa uploaded to a brand new EPROM, because I suspected that the original was bad, but there is no difference.

http://vogonsdrivers.com/getfile.php?fileid=947&menustate=0

I have double-checked all the jumpers and they all appear to be accurate for the cache, CPU settings, RTC operation, CPU voltage, multiplier, etc.

Would a dead RTC with the wrong CMOS settings cause this? I know that they can cause a lot of trouble. I would just take it out, but this one is going to be very difficult, and I don't have a desoldering station, so I am trying to rule out everything else first.

You guys are knowledgeable, and this board has a lot of support, so I would really appreciate your thoughts.

Thank you...