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386 Battery issue

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TheLazy1

Experienced Member
Joined
Jun 2, 2009
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370
Location
Toronto, Ontario, Canada
I have a nice little 386 board here which had it's battery clipped at one point, which is fine but so far replacing it hasn't been successful.
Okay, I made one mistake...

I soldered a coin holder onto the original battery contacts before remembering that they would recharge...
It wasn't for very long though and I ended up moving it to the ext battery connector but it still doesn't keep the settings.

Maybe the board requires 5-6v?
I didn't want to throw more voltage at it unless I was sure.
 
Although some boards had the jumpers placed on the external battery connector itself, there were others that had a separate jumper somewhere else that selected which battery to use. Have you found and correctly set that jumper, if applicable?

IIRC they do use 6 volts, typically a holder for four AAs on the 4 pin external header (so a single CR2032 isn't going to do it)...but that could easily vary from board to board, so best to confirm it first with regards to your specific board.
 
Best thing to do would be to find the manual or TH99 page for your motherboard to make sure that it isn't, for whatever unlikely reason, on the other side of the board...

Such a thing might also tell you exactly what it wants plugged into that connector.
 
OK, that's the TH99 page. Indeed, frustratingly bare.

I'm guessing yours was one of the ones that just put the jumpers on the 4 pin connector itself to select internal battery. So, in that respect, you should be alright...just need to provide the right power (and of course with the right polarity).

Can anyone else chime in confirming that 6V (ex. 4 AAs in series) was the common setup?
 
Yes, 6 volts is standard for the battery connected to the 'external battery' Berg connector.

3.6 volt batteries are also used by some people, but they probably don't last as long. On some motherboards, a 3.6 volt battery may not be adequate (example: http://members.dodo.com.au/~slappanel555/misc/5170_battery_3.6v.htm).

And I too would expect to see a jumper to switch between internal and external battery operation. It was the standard way that was done.

5170_battery_4_x_1.5v.jpg


5170_battery_6v.jpg
 
TheLazy1 said:
I should have written more clearly, I meant stacking 2 3.3v coin cells.
I'm guessing the answer is still no though. :D
Click to expand...
It's not going to be a problem.

If you are soldering those cells, be aware that there are dangers in that practice - search the Internet.
 
1. Are you positive (pun intended) that your 'battery' is connected in the correct polarity?

2. There still might be an 'internal/external battery' jumper that has yet to be changed. Is there a jumper on the motherboard for which you haven't identified its purpose?
 
More issues!
The date is kept but it seems that time does not advance.

I decided to run DOOM for a timedemo and it appears to be running in slow motion, removing the CMOS battery causes it to hang at I_StartupTimer so I don't know if that's it.
SpeedSys Hangs at checking for the Year2000 bug.
CacheChk Counts all 128KB but says I only have 1 cache. (Edit: AMD 386-DX40 has L1 right?)

Could it be a 3v system and I'm mistakenly overvolting it?
I mean, it didn't work at first because of a 1 pin offset. I hope the board isn't damaged. :(

[Edit]
Doom results may be normal for this CPU, but speedsys still hangs.
386 Does not have L1, oops! :)
 
Last edited:
Sorry for rezzing this old thread but I've grabbed this board again to try it out.

Current symptoms:
Date/time kept but time does not increment.
Floppy does not work.

I tried putting 6v on the ext battery connector and all it does is give a floppy error sometimes making the floppy do erratic stuff.
Any ideas where to look?
 
The time does increment while it's on but appears to stop when the power is off, the floppy was used on another board and worked fine.
With 6v on the external battery port it'll randomly come up with FDD Controller Failure though.
 
TheLazy1 said:
The time does increment while it's on but appears to stop when the power is off, the floppy was used on another board and worked fine.
With 6v on the external battery port it'll randomly come up with FDD Controller Failure though.
Click to expand...

Did you settle on the stacked CR2032 batteries? I'm going to be doing the same thing with my 386 mobo once I get the battery housing. (It holds two coin cells for 6v) So far my rechargable battery is doing great, and keeps excellent time. My mobo looks a lot like yours (it's an Acer) but there is no jumper for external battery on my board. Are your batteries new? My board ALSO has a realtime clock (a Motorola chip that is powered by the battery as well as the CMOS.)
 
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