Hello, I recently registered in the forum, but it has been a couple of years since I usually go through info, it is an excellent community and I should have registered before.

Getting to the point ... last week I bought an ibm pc 330 socket 3 and it came with a 387mb and 16mb ram 72 pin SIMM disk and since then it has been giving me various headaches to get it to work well ... And I didn't get much!
As soon as I plug in the psu, the pc starts up and the pwr button (momentary) and the front LEDs don't work, the integrated video doesn't work either and I always get error 161 (cmos battery faulty). So far I have only managed to get it to give me an image and to start it using an ISA vga board and setting the cmos jumpers to "clear", but if I go into the bios settings and want to save and exit, the pc freezes and I have to turn it off , move the cmos jumpers, to then be able to start it again. If I exit the settings without saving anything, I can boot from floppy drive or hdd without any problem and run programs, etc.

So far I did:

- Change the cmos battery for a new one
- Clean the motherboard well with an antistatic brush
- Replace the source with a normal AT that I know works perfectly
- Update the Bios for a newer version
- Change the processor (I486DX-33), for another (I486DX-33)
- Test each stick of RAM SIMM 72P
- Boot with only RAM + VGA ISA
- Remove the BIOS chip, clean the socket with isopropyl alcohol and reinsert it in the correct position
- Disconnect the front LEDs
- Testing a lot of possible configurations with the motherboard jumpers

And so far I couldn't solve anything

The problem is exactly the same as the one experienced by user TheAbandonwareGuy with an IBM PC 350 (link is below)

I'm really stuck, if anyone knows how I could walk this bug out I'd really appreciate it

Link that I mentioned previously:
Bought these (retro) hardware today

Another link of a guy with a similar problem:
Re: A problem with 486 motherboard