Victorkorp99 wrote on 2021-02-16, 08:23:

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 […]
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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

Hi there
I want to resurrect this old topic, cause I've just recently got the same machine - and the behaviour is completely same as for Victorkorp99.
I can enter BIOS and save settings, but after a reboot it won't enter BIOS again (just freezing), until I reset BIOS with the jumper. After reset I can enter BIOS again. I already reflown almost all the chips on the board to avoid cold joint. Inpected for broken traces, but nothing helps. @Victorkorp99 - have you managed to fix the issue? Maybe you remember since 2017)))
I also noticed that after I enter BIOS - the date might be wrong, usually it's been reset to 00-00-1900 (which is not correct, as should be 01-01-1900), but sometimes those values for date might be completely corrupted i.e. 34-51-1954
It seems to me that maybe 82C602 has gone bad... Seems like storing BIOS settings is wring wrong values to the RTC module which lives inside 82C602 chip and next time you enter BIOS - it's trying to read corrupted values from RTC and freezes. I might be wrong however.

Any help is appreciated. Thanks in advance.