OT:CMOS checksum error

The control computer is an old P4 with ISA slots. It sat on the shelf quite a while and the battery totally died. I haven't bought a new
one.
Anyway, it needs a non-default CMOS setup. On boot, it gives a message "CMOS checksum error, loading default settings"
If I sit there and hit delete and edit the CMOS it boots and runs fine,
Long shot, any chance this is repairable? Is there a chance its just the PC battery? PCs with an ISA slot are hard to find.
Project update, installed and debugged all I/O needed to run without the tool changer over the last few days. Encoders are next, should only take a day,maybe two. Then some time running the hydraulics to make sure the counter balance and spindle gear shift work. As soon as I get something to make those dang DB connectors, this baby is gonna roar!
Karl
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Yep, needs a battery.
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The local Interstate battery dealer spot-welded solder tabs onto a CR2016 for my old laptop. Don't try to solder directly to the cell.
jsw
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Jim Wilkins wrote:

Or you can do what I generally do, You can buy a coin cell holder that fits the 2032 cells for about 30 cents. Has wires on it and I just install that if the machine takes an oddball.
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"Steve W." wrote:

I pull the sockets off bad motherboards.
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Not in my tightly packed laptop.
The OP doesn't want to solder DB25 pins.
jsw
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Karl Townsend wrote:

Unplug the computer. Change the battery. Momentarily short out the "clear_cmos" pins with a jumper (or a screwdriver).
Plug it back in and you should be good to go. Remember that this procedure will clear out any custom values, if any exist, in the BIOS chip.
Jon
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Years ago I bought a 386-20 that had a battery holder under the floppy drive bay for 3 AA batteries. The manual indicated that was for when the button cell died. They were thinking back there in 88 or 89.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
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"Gunner Asch" wrote...

If you go for NiCads, it'll need 3 - they only make 1.2 - 1.25 fully charged, but the voltage stays relatively constant until they're *completely* flat. Otherwise - yes, replace the battery, good plan and cheaper than Fleabaying for a new ISA slot mobo!
Dave H.
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On Nov 7, 8:02am, "Dave H."

When I get to design the battery backup circuit I use NiCads and trickle-charge them, but otherwise Alkaline or even better Lithium AAs will last much longer. The CMOS current requirement is so low that the battery lasts for essentially its shelf life.
jsw
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Gunner Asch wrote:

I once made $60.00 on a ten-minute service call - it was a Compaq, which needs a custom Compaq battery; the only thing I could come up with was to tell the client to go to the Compaq store and buy one; I showed them how to swap it out, and they wrote me a check. :-) (this was in the early 1990s, when $60.00/hr was a pretty reasonable rate.)
Cheers! Rich
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wrote:

\
Yes, that symptom is exactly what a dead battery does. Either locate the battery and replace it, or (sometimes) if the battery is a soldered-in-place NiCd rechargeable (the usual configuration is three button cells in series to make a ridged cylinder), you must REMOVE IT (cut the tabs, no need to resolder) and plug a battery onto the nearby battery connector.
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whit3rd wrote:

Some use a tiny coin cell inside the real time clock module. An old 'Dallas Semiconductor' DS1287. I've removed the cover and the old cell, then soldered wires to the pins for a chassis mounted coin cell holder.
Here is a website explaining another way to do the modification:
<http://www.classic-computers.org.nz/blog/2009-10-10-renovating-a-dallas-battery-chip.htm
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