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Help! Micronics/Gateway 2000 486 Motherboard Mysteriously Dies

modem7 said:
In my opinion, NiCd battery leakage [photo] is insidious. Look up the definition of that word to gain an appreciation of its meaning.

Have a very good inspection of your motherboard; the 'leakage' may have got to places that are well hidden.

See the motherboard at [here], one which suffered from such leakage on a card. Not only did the motherboard have a few faulty chips right near the card's slot, but there were damaged vias as well - you guessed it, around the general area of the slot. The green wiring is my bypassing of the faulty vias. No track damage. That motherboard would have probably stopped working at the time when the first chip, or via, was damaged. The remaining damage happened after that. The faulty chips near the card's slot suggested to me that the leakage worked its way into the chips.

I still have a friend's faulty IBM 5170 motherboard, from years ago. The battery had leaked, resulting in (indirect) damage to the area around the keyboard connector. That was repaired and then the motherboard worked. But only for a while. I suspect that even though I had thoroughly cleaned the affected area of the motherboard, that the 'leakage' had already made its way into bits (i.e. my cleaning affected the surface only). Something like that. It's just a hypothesis.

I am not saying that your symptoms are caused by damage resulting from NiCd battery leakage, but such damage is certainly a possibility.

You are seeing changing symptoms after physical influence is applied. Coincidence, or is this a damaged track/via/joint !

Maybe the Deoxit will be the fix.
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Hey @modem7,

Thanks for the information. Battery leakage is definitely insidious. I had a real close up inspection of my board with a magnifying glass and couldn’t find any hints of corrosion, battery leakage or broken traces.
 
Alright everybody,

I’m at a complete loss here. Over the past couple days, while waiting for the Deoxit to come in, I’ve just been powering on the machine whenever I walk by it. It seems to consistently boot up now, but my settings never save. Whenever the board tries to reboot, (or reset, whatever you want to call it) the board locks up. Then I get that [A0][09] code for a couple attempted boots, and then inevitably the board boots again and the cycle repeats itself.

Today, the Deoxit came in. I caked the connectors in it, and worked them all through like I was suggested. It made no difference. Cosmetically, the board now is absolutely spotless.

Therefore, I just have no clue what to do. Seems like I’ve tried everything. Feeling a little down here.

Thanks to everyone who helped me out, any final suggestions would be most welcome. Otherwise, I will begin my search for an exact replacement.
 
It looks like you have an external CMOS battery. Is the voltage low?
 
Plasma said:
It looks like you have an external CMOS battery. Is the voltage low?
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Unfortunately not. The CMOS battery pack I’m using is good and tested in another 486 of mine.

Even so, I’ve worked on this type of motherboard before. I know it should be able to reboot without any CMOS battery and it should be able to be reset without locking up.

Thanks anyway for the help @Plasma!
 
Give me a few days to let me foot/ankle heal. I'll drag down the 486 I have and we'll go through some measurements if you have a multi-meter.
 
bostonvintage1993 said:
Unfortunately not. The CMOS battery pack I’m using is good and tested in another 486 of mine.

Even so, I’ve worked on this type of motherboard before. I know it should be able to reboot without any CMOS battery and it should be able to be reset without locking up.

Thanks anyway for the help @Plasma!
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You might be surprised at the weird things that can happen when CMOS RAM gets corrupted. Not saving settings and not rebooting are common symptoms. If you are sure the battery is good, I would suspect the chip (6818).
 
Eh easy to test that theory, and just remove the battery altogether, and see if the same symptoms remain.
 
Not necessarily. Removing the battery will not cause a stuck bit.
 
Plasma said:
You might be surprised at the weird things that can happen when CMOS RAM gets corrupted. Not saving settings and not rebooting are common symptoms. If you are sure the battery is good, I would suspect the chip (6818).
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Thanks for the advice! That would make a lot of sense, but I’m a little confused as to which chip on the motherboard you are referring to. Is it socketed? Let me know, thanks again!
 
Well lets look at what you mentioned earlier, if you press down on the power connector it boots fine? I would look at the solder points for those pins next. Maybe one has a dry/cracked solder joint? I had a situation a few months back, on an XT, that was similar. I found the power supply AT connector socket for the "Power Good" signal, to be loose, and would cause the board not to fully post. So perhaps check all pins are making good contact with the connector.
 
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twolazy said:
Well lets look at what you mentioned earlier, if you press down on the power connector it boots fine?
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Hi @twolazy,

For some reason, I can now get it to boot every time with no pressure to the power connector. Maybe the Deoxit did something there. The board always boots now, but I can’t press the reset button or save and exit the CMOS settings without it locking up. I then have to power cycle to get the board to boot again.

It seems CMOS related, and yesterday a new symptom occurred. Sometimes, when I am trying to set settings in the BIOS setup, the clock present in the BIOS setup will show random characters instead of numbers in the seconds area. For example, sometimes the seconds will count as 0=, then 0>, then 0!, or some other random assortment of characters when it should be counting seconds (01, 02, 03).

Not sure what that means - this is why I thought it may be CMOS related and why I thought the chip may be the culprit, but seems I was wrong. Any help from anyone would be greatly appreciated!

Thanks so much!
 
I would reseat the bios chip then, with a little deoxit in the socket. BE VERY CAREFUL AND GENTLE. These aged sockets love to crack on you. Just take yer time, and pry it up from opposing corners a little at a time.

 
So I was able to get up the stairs today, and took apart the 486. I'll try to get the board downstairs tomorrow with a power supply and video card. Its not exactly the same board but its nearly 99% identical, so should be close enough for testing yours.
 
twolazy said:
I would reseat the bios chip then, with a little deoxit in the socket. BE VERY CAREFUL AND GENTLE. These aged sockets love to crack on you. Just take yer time, and pry it up from opposing corners a little at a time.

Click to expand...
I reseated the BIOS chip just now. I now get this phenomenon in the CMOS setup.

I still can’t hit the reset button or reboot from the CMOS setup without the board locking up.
 
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