Ok, so I think I have some idea after doing some searching of what it is and what it looks like so I took my PCChips M919 motherboard [such a total POS motherboard] and i'd never be using it again so I desoldered off the coin-style battery holder.

Now I just need to get a wire of some sorts, could I hack this wire to work with the 2-pronge coin-style CMOS battery holder?

Thanks. 😎

I've used a PC speaker wire with success. From memory though those coin batteries are only 3V, and some boards require more - 3.6 maybe? Give it a try, but if your board can't remember what time it is, then suspect the battery.

You can for sure make a CR2032 mod, i actually modded all my 386 boards and it works ok. But keep in mind that in those days barrel type batteries were rechargeable, so when the Computer is on current will go to the battery. You might want to use a schottky diode ro make the current flow unidirectional so that it prevents a CR2032 from being recharged.

Doing so, should be fine and will avoid possible nasty consequences. And also keep in mind what badmojo said, about 3.6V vs only 3V.

Just connect a coin battery to J1, set the jumper to use that one and you should be fine. There is this voltage difference mentioned (3,6 - 3 volts) but I've never encountered a single board not holding its data with a 3V coin battery. I've even used 2 AA's taped together in such cases 😀

No need to mess with recheargable batteries since the board has a connector for an external one. Not only it'll save you the trouble of soldering on the board, but also keep in mind that even if you do decide to replace the recheargable battery on the original location, the new one has to be of the same type. For example, if the original was a Ni cad barrel, it't not advisable to replace it with a modern Li-ion recheargable coin (they charge differently).

konc wrote:

but I've never encountered a single board not holding its data with a 3V coin battery.

My 486 mainboard insists on 3,6V. UMC chipset, VLB slots.

gerwin wrote:

konc wrote:

but I've never encountered a single board not holding its data with a 3V coin battery.

My 486 mainboard insists on 3,6V. UMC chipset, VLB slots.

Well... you got me here 😀 Still, rule of thumb is that it that most probably it'll be OK, but I'm intrigued by this exception

I'd be inclined to wire a 3 cell AAA holder of NiCd or NiMH to the connections of the barrel battery - not sure if the trickle intended for a smaller pack would keep them topped up though.

Some older motherboards had an external battery connector. If it doesn't, then you can actually still obtain replacement NiCd batteries which you can just solder back onto the motherboard where the original battery was.
I've recently had to remove my 386 motherboard's NiCd 3.6V battery as it was starting to show signs that it was leaking (despite it still managing to keep the time - after all these years).
I then plugged in a 3x AA (1.5V x 3 = 4.5V) battery holder but, it wasn't keeping the time.
I then had to up the voltage by adding another AA cell (1.5V x 4 = 6V) and sure enough, now it's keeping it's time.
However, it is true that, with some newer 486 motherboards (that still utilised the NiCd batteries), 3V might be sufficient.
Below is a link to a website I found that provides all the information you need.

http://pc-restorer.com/replacing-cmos-batteries-in-old-pcs/

I was looking through my closet and found the perfect female-to-female jumper wire, I connected the black to the Battery Cathode (-) and red to the Battery Anode (+) on the coin-style holder and J1 jumper on the motherboard and it seems to be working great. 😁

My 486 uses a 4.5V internal battery. 3xAA or 3xAAA (kept away from the board!) is a decent solution.
It's been almost a year since I installed it and no problems so far.

Both of these below are the ones I used before, without a single problem in 386/486 PCs. I asked before the same question, and suggestions are for 4xAA more than 3xAA. And yes, I also used old speaker connectors to mod them.

For a while I used that one displayed at the bottom. But in one battery compartment I put an M6 Hex Bolt, as to short it. Giving 4,5 instead of 6 V.

konc wrote:

gerwin wrote:

konc wrote:

but I've never encountered a single board not holding its data with a 3V coin battery.

My 486 mainboard insists on 3,6V. UMC chipset, VLB slots.

Well... you got me here 😀 Still, rule of thumb is that it that most probably it'll be OK, but I'm intrigued by this exception

I would have preferred the compact 3V coin cell setup, even added the holder. but it won't work...
Also looked around for these 3,6 V coin cells LIR2032, but these are either a little expensive or suspiciously cheap...

Last year I ruined a MOBO with a self built solution I believe. I either put in a 4.5 or 9 volt battery to the external hookup to replace this rechargeable external battery that had been in there. It did not recharge. But that is different from a cell battery setup obviously.

I have successfully used a coin battery in place of an external Lithium rechargeable battery on my 386 system! All I did was desolder a holder from a dead mobo and then I wired that to a clipped fan wires and plug and plugged it right in. As long as you match the polarity you should be good. 😁

Too late now. 😀 I scrapped the PC after the MOBO failed: VGA & FDD & IDE on board failed. And with plug in cards it died as well after a while. 🤣

carlostex wrote:

You might want to use a schottky diode ro make the current flow unidirectional so that it prevents a CR2032 from being recharged.

carlostex, thanks for the heads-up.

I'm using the CR2032 mod on my ASUS ISA-486. Since there's no manual for that early board, I don't actually know if the original external was/wasn't rechargeable. Hadn't thought about it till now. And of course putting a regular cell in a rechargeable's position is just asking for fire down the road. So thanks for that. I've just dragged the 486 over to the bench for attention next time the iron is warm.

gerwin wrote:

I would have preferred the compact 3V coin cell setup, even added the holder. but it won't work...
Also looked around for these 3,6 V coin cells LIR2032, but these are either a little expensive or suspiciously cheap...

Those are Li-ion rechargeables, although in practice it won't make any difference (except from shortening the battery's life), in theory it's not right to replace a Ni-cad etc with a different type, as I said earlier they charge differently. Again, this is just for the discussion and practically safe to try...

pewpewpew wrote:

carlostex, thanks for the heads-up.

I'm using the CR2032 mod on my ASUS ISA-486. Since there's no manual for that early board, I don't actually know if the original external was/wasn't rechargeable. Hadn't thought about it till now. And of course putting a regular cell in a rechargeable's position is just asking for fire down the road. So thanks for that. I've just dragged the 486 over to the bench for attention next time the iron is warm.

No worries. The diode will never hurt since if you orient it correctly it will only allow current from the coin cell to the motherboard and not the way around. A coin cell being recharged could result in disastrous consequences. So i will always recommend this when doing a CR2032 mod.

Is it possible to just buy one of these and plug in in? http://www.ebay.com/itm/IGT-SLOT-MACHINE-LITH … =item231e0d28f6

Surely these new batteries don't leak like the old ones do?