MS 4125 - external battery

Discussion about old PC hardware.

MS 4125 - external battery

Postby Marwood82 » 2019-8-14 @ 08:45

I've just picked up a MS 4125 board. A previous owner has already removed the old CMOS battery and i'm looking at how to sort out connecting a new one.

Looking at the board description here ... N-2-1.html

It does list the option of an external battery.
However I'm a bit confused on how to hook one up given how the settings are described.

It lists J4 as being the external battery connector.

Then it also lists that J4 is the selector for internal/external battery

Battery type select internal - J4 pins 2 & 3 closed (This is how it is currently set up)
Battery type select external - J4 Closed

Apologies if this is a really dumb question, but how do I connect an external battery to J4 whilst at the same time closing all 4 pins?

Also, I don't suppose anyone has a copy of the manual for this thing?

I've googled high and low but that link with the jumper settings is the best i can find.


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Joined: 2019-8-14 @ 08:14

Re: MS 4125 - external battery

Postby TheMobRules » 2019-8-14 @ 16:25

The external battery is connected to the two outer pins (1 & 4) of the header, with a 4-position connector like the one used for plugging the PC Speaker. The two middle pins remain unconnected when using the external battery.

External batteries

You need to correctly identify which pin goes to the battery + and - terminals, usually pin 1 is + and pin 4 is -, but I have seen cases where the opposite is true, so you better check that with a multimeter before connecting.
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