The bios chips are the square-ish socketed ones.

there's two, one for the high byte and one for the low byte.

weedeewee wrote on 2022-12-30, 09:50:

The bios chips are the square-ish socketed ones.

there's two, one for the high byte and one for the low byte.

thanks, so maybe it's just a matter of cleaning the contacts? what else could it be?

I am also slightly worried about the round gunk/dirt traces next to my jumper wire. Could those be signs of battery or capacitor leakage?

cojoc09 wrote on 2022-12-30, 10:32:

weedeewee wrote on 2022-12-30, 09:50:

The bios chips are the square-ish socketed ones.

there's two, one for the high byte and one for the low byte.

thanks, so maybe it's just a matter of cleaning the contacts? what else could it be?

I am also slightly worried about the round gunk/dirt traces next to my jumper wire. Could those be signs of battery or capacitor leakage?

Those are likely stamps, not signs of battery or capacitor leakage. Seem to have a number in them.

cojoc09 wrote on 2022-12-30, 09:21:

Hi all ! I received an old Halikan 386sx laptop from a friend (it as a thrift shop find) and for some reason it won’t boot. All […]
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Hi all !
I received an old Halikan 386sx laptop from a friend (it as a thrift shop find) and for some reason it won’t boot.
All that it displays is CMOS inoperational System halted.

I found a broken trace and used a jumper wire but that didn’t change anything.

I removed the old cmos battery and soldered a cr2032 holder but it seems the battery is not the problem. The hard drive spins up maximum speed for about 5 seconds, then stops completely. Then it starts again, not sure if this means anything.

I am not even sure which chip is the BIOS, googling the code/names on them doesn't help much. If I could identify which one is the BIOS chip, maybe I could test for continuity on those traces.

Any ideas would be appreciated.

Thanks!

Hi,

I suppose it's not about BIOS but rather a RTC (real-time clock) section of the chipset. Maybe something is wrong with circuit of VL82C331 chip where RTC and CMOS memory "live".
I mean the chip is probably good but it might be broken wires or broken crystal 32kHz or cold joints

Roman555 wrote on 2022-12-30, 15:18:

Hi, […]
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cojoc09 wrote on 2022-12-30, 09:21:

Hi all ! I received an old Halikan 386sx laptop from a friend (it as a thrift shop find) and for some reason it won’t boot. All […]
Show full quote

Hi all !
I received an old Halikan 386sx laptop from a friend (it as a thrift shop find) and for some reason it won’t boot.
All that it displays is CMOS inoperational System halted.

I found a broken trace and used a jumper wire but that didn’t change anything.

I removed the old cmos battery and soldered a cr2032 holder but it seems the battery is not the problem. The hard drive spins up maximum speed for about 5 seconds, then stops completely. Then it starts again, not sure if this means anything.

I am not even sure which chip is the BIOS, googling the code/names on them doesn't help much. If I could identify which one is the BIOS chip, maybe I could test for continuity on those traces.

Any ideas would be appreciated.

Thanks!

Hi,

I suppose it's not about BIOS but rather a RTC (real-time clock) section of the chipset. Maybe something is wrong with circuit of VL82C331 chip where RTC and CMOS memory "live".
I mean the chip is probably good but it might be broken wires or broken crystal 32kHz or cold joints

I didn't check the underside of the motherboard, maybe I can look for cold solder joints. Anything else which can be checked?

cojoc09 wrote on 2022-12-30, 17:09:

I didn't check the underside of the motherboard, maybe I can look for cold solder joints. Anything else which can be checked?

First I would carefully and discreetly check pins of the chips with a toothpick or a needle. Maybe one or more pins are not soldered properly. VL82C331 is on the top side. Of course the power supply or batteries should be disconnected before

P.S. VBAT pin is #116 - should be some voltage to supply the cmos memory
Power sense is #117 - IMO, should be some voltage too

Roman555 wrote on 2022-12-30, 18:06:

First I would carefully and discreetly check pins of the chips with a toothpick or a needle. Maybe one or more pins are not sold […]
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cojoc09 wrote on 2022-12-30, 17:09:

I didn't check the underside of the motherboard, maybe I can look for cold solder joints. Anything else which can be checked?

First I would carefully and discreetly check pins of the chips with a toothpick or a needle. Maybe one or more pins are not soldered properly. VL82C331 is on the top side. Of course the power supply or batteries should be disconnected before

P.S. VBAT pin is #116 - should be some voltage to supply the cmos memory
Power sense is #117 - IMO, should be some voltage too

Many thanks for all this info, I will check and report back in this thread

"CMOS inoperational" is not a battery issue, it's a BIOS POST error when a value written to NVRAM cannot be read back. So the first question to answer is why was that trace damaged? Corrosion? Short-circuit? Screwdriver jab? If one trace is damaged, there might be more. Shorted chips can easily get damaged, and corrosion can cause shorts too. Since you already found a problem with the mobo it's a good idea to investigate why it happened, this often saves you time figuring out what needs to be repaired/replaced, or even if it's possible at all.

Deunan wrote on 2022-12-31, 21:19:

"CMOS inoperational" is not a battery issue, it's a BIOS POST error when a value written to NVRAM cannot be read back. So the first question to answer is why was that trace damaged? Corrosion? Short-circuit? Screwdriver jab? If one trace is damaged, there might be more. Shorted chips can easily get damaged, and corrosion can cause shorts too. Since you already found a problem with the mobo it's a good idea to investigate why it happened, this often saves you time figuring out what needs to be repaired/replaced, or even if it's possible at all.

I can't say for sure but one trace was simply "floating" above the PCB, as if it was pulled out. Maybe someone forced a component out and pulled the trace?

Well, I can't be sure since it's not a board I'm familiar with, but there is a footprint on the PCB right below the red wire that looks like it had one of those small barrel 32768Hz crystals, and a wire securing it going over from side to side. On the photo it looks like the wire has been cut and the crystal desoldered, for whatever reason. Perhaps someone already tried to resolve the CMOS error issue? But from my experience a dead crystal will just stop RTC from advancing and the BIOS never checks if it actually works. Well this one might be I guess.

a missing RTC crystal could be the culprit . me thinks.

Deunan wrote on 2023-01-02, 14:00:

Well, I can't be sure since it's not a board I'm familiar with, but there is a footprint on the PCB right below the red wire that looks like it had one of those small barrel 32768Hz crystals, and a wire securing it going over from side to side. On the photo it looks like the wire has been cut and the crystal desoldered, for whatever reason. Perhaps someone already tried to resolve the CMOS error issue? But from my experience a dead crystal will just stop RTC from advancing and the BIOS never checks if it actually works. Well this one might be I guess.

It seems that spot on the PCB is empty by design, I found a video of this exact same laptop and at this time stamp (7:32) you can see that there's nothing on the PCB in that spot unfortunately. And his laptop works. https://youtu.be/vh82eCbVBaU?t=452

cojoc09 wrote on 2023-01-07, 09:56:

It seems that spot on the PCB is empty by design, I found a video of this exact same laptop and at this time stamp (7:32) you can see that there's nothing on the PCB in that spot unfortunately. And his laptop works. https://youtu.be/vh82eCbVBaU?t=452

Good spot. No, I'm still pretty sure it's there, except on the other side of the PCB. It bugged me that there is also a space for SMD variant and the pads are exposed and could be shorted, but it's not a problem if the THT part is on the other side. Not sure why I didn't realize that sooner.

Anyway, a missing RTC crystal is usually not causing such issues but it was worth investigating. I assume you've installed the CR2032 holder the correct way? And you do have a battery in there. Test the voltage on the holder pins to make sure the mobo is not shorting the battery - some designs require that battery to be there and not be flat or the CMOS will not work. These are rare though and usually take much bigger battery than a coin cell. What of the original battery, was it a NiCd? Did it spill or vent? Corrosion from these damaged many boards...

Deunan wrote on 2023-01-08, 20:02:

cojoc09 wrote on 2023-01-07, 09:56:

It seems that spot on the PCB is empty by design, I found a video of this exact same laptop and at this time stamp (7:32) you can see that there's nothing on the PCB in that spot unfortunately. And his laptop works. https://youtu.be/vh82eCbVBaU?t=452

Good spot. No, I'm still pretty sure it's there, except on the other side of the PCB. It bugged me that there is also a space for SMD variant and the pads are exposed and could be shorted, but it's not a problem if the THT part is on the other side. Not sure why I didn't realize that sooner.

Anyway, a missing RTC crystal is usually not causing such issues but it was worth investigating. I assume you've installed the CR2032 holder the correct way? And you do have a battery in there. Test the voltage on the holder pins to make sure the mobo is not shorting the battery - some designs require that battery to be there and not be flat or the CMOS will not work. These are rare though and usually take much bigger battery than a coin cell. What of the original battery, was it a NiCd? Did it spill or vent? Corrosion from these damaged many boards...

Yes, a new CR2032 is installed correctly. Yes, previous one was NiCd and it only spilled in the empty battery compartment and not on the motherboard

Well, I'm still suspicious about that broken trace because I don't have any other ideas. The mobo seems to kinda work if it boots far enough to show a message on the screen, except the CMOS part. I wonder if that broken connection went anywhere elese, like if there is a via nearby that it connected to and now isn't?