Hi!

Can it be a defective psu? How many simms does that machine has? Try it with only 2.

sure, the PSU is kind of a cheap-ass one. check out the photo I've linked in my opening post, there are no SIMMs, it has DIP memory chips and half of them are soldered so i'd have to put the board out to remove or swap them (makes me wanna puke)...

OK after the Video Test of checkit (which runs fine) it says that there were memory parity errors. however they don't appear when I do the memory test using checkit.
so i conclude that maybe really the PSU's voltage might be dropping at higher load (graphics card utilization) which causes memory errors.

too lazy to hookup the scope, however...

I have overcome myself and hooked up the scope to the supply lines. Everything hunky dory. Just to be sure I tried two other PSUs, no luck
I already changed the VGA card to a TSENG ET3000 with 256k of memory -> no luck, still parity errors

should I change other things like HDD and I/O controller?

Or is it likely that the motherboard (maybe some tantals or memory chips) is defective?

Thanks!

now that's strange.

there are 36 pieces of 16 pin DIP memory chips on there. half of them read MSM41256A, which are 262144-WORD x 1-BIT Dynamic RAMs.
Those 18 MSM41256A are socketed, so I pulled them out. The BIOS still recognized 512K as before, so I guess the chips which I pulled out weren't active and the whole memory incl. the pulled out chips would be 1MB.

One of the pins of the chips I pulled out was completely bent and made NO contact to the socket.
Now, without those 18 chips, everything seems to work just fine.

If the memory was not used (i.e. disabled), how can this have caused memory parity errors?

Thanks!