First post, by imi
edit: I'm just going to keep using this thread for my problems with this build, the cache issue is solved, see below for new issues ^^
Ok, I'm at a loss here... I got a nice little 386DX40 board from a box of stuff:
The board had two W24257AK-15 cache chips on it, one in U10 where the TAG cache sits according to the layout, and one in U11.
I did not further investigate this at first (as in look up the board or cache setup) I just tried turning it on, and it would not post, I held my finger on the CPU and gpu to see if they're warm... and when I wanted to turn it off again I accidentally slipped with my finger over the cache and almost burnt myself, they were scorching hot.
I had a really hard time taking the cache out because they were jammed in the sockets and there was no space really between the ISA and ram slots.
After I removed the cache the board bootet up.
So far so good... cache defective? can they really get that hot if they're defective?
So after looking up the board and reading a bit it says there should be one 8K x 8 in the TAG socket and 4 32K x 8 in the cache sockets
the chips that were in it are both 32k x 8... so now I got one W2464AK-20 8K x 8 for TAG and 4x W24257AK-20 32K x 8, this should be the correct setup?
This time I put some cut cable ties underneath the chips so there would be a little bit of wiggle room to get them out again and put them in.
...turned the power on... and saw smoke rising 😵 immediately turned it off again, and yes... the cache was scorching hot again, I couldn't even touch it, almost burnt my finger again just trying, it was maybe on for a second.
I assume the smoke came from the plastic of the cable ties underneath and not the cache chips themselves...
so did I just kill a bunch more cache chips? or are all of them defective? 😵
I can't see any obvious fault or damage on the board apart from the missing battery.
does anyone know what could cause the cache to just burn up immeaditely upon turning on the system?
Luckily the board did still turn on after removing the cache again, phew.
I don't want to kill the board or more cache chips by trying out stuff, so I thought I'd ask if anyone knows what could be the culprit here?
Thanks in advance.
edit... okay call me crazy but... uh I just measured the sockets with my multimeter, and VSS/VDD seem to be entirely the other way around
are they just inserted the wrong way?
if so, the picture on TH99 is wrong, as it shows the notch towards the ram slots, and apparently the old cache was also inserted this way.