It has been seen in the wild with CR2032 holder mounted, such as in the pic here... https://www.ultimateretro.net/en/motherboards/6675
The IDE drivers should enable 32bit DMA transfer modes which will speed disk access up a bit in windows, they may work well in DOS also, but beware of older software in DOS that hammers the BIOS routines or hardware directly and might screw up.

Okay. So if I was going to use Windows 95 then the IDE drivers would speed up drive access in Windows, otherwise the 3-4MB/s I am getting in DOS is as expected. I saw in that picture on the Win3X that they had a cr2032 battery holder installed, but I cannot see if there any additional diodes or parts added to block recharging the battery?

Here are the pictures of the motherboard.

This one is the motherboard overall -

This one shows the model number that is listed on the motherboard -

And finally this one shows the connector labeled J1 near the AT port on the board -

When looking on the Win3x website there is no dump of the BIOS, is that something that would be wanted as well?

Absolutely, but don't use win3x anymore for this, use ultimateretro.net !

Seeing J1, I would make a guess, lacking further info, that the 5-6 pins nearest the keyboard connector will want a jumper for external battery enable and the pins 1-4 are where the external battery plugs in. But that's just based on seeing similar configs not this particular board.

The jumper settings sheet I found indicated JP11 has 3 different settings. 1-2 indicates use of internal battery, 2-3 indicates use of external battery, and 2-3 resets CMOS. JP11 is in a different area towards the middle of the board. So, if that information is correct, I still have no clue what J1 is. It doesn't appear to be a jumper point because this board very much labels everything that is to have jumpers with JPxx. But as is normal with this sort of thing, I am more than likely wrong. If you all think I would be safe attaching a CR2032 battery holder to the board in the specific spot, then I can do that. I have 4 or five more of the coin holders from my prior project. Also thank you for the pointing me to Ultimateretro.net. I will be sure to bookmark it.

Oh, if there is an indicated battery jumper then J1 is next most likely to be a PS/2 header.

Oh, so J1 could be a PS/2 Mouse header? That thought never even occurred to me. That still brings up the question of where I plug in the external battery then. Nothing particularly stands out to me as being a connector for an external battery even though it states that it can take one. It will probably have to stay a mystery to me for now. Thank you for the information so far. I really do appreciate it.

It should be J11 that controls the internal/external battery connection, not JP11, correct? It looks like it would be that 4 pin header closest to the battery connector. It would make more sense to be located there as well.

nathanieltolbert wrote on 2021-11-11, 00:36:

Oh, so J1 could be a PS/2 Mouse header? That thought never even occurred to me.

You're lucky.

turbooo wrote on 2021-11-11, 18:46:

It should be J11 that controls the internal/external battery connection, not JP11, correct? It looks like it would be that 4 pin header closest to the battery connector. It would make more sense to be located there as well.

Oh, you're correct. It is labeled J11 and not JP11. The 4 pin header closest to the battery is J36. It appears to have a + and a - silkscreened on the board next to the connector. I do not know if that is for that pin header, but I see nothing else nearby. I don't see anything in the jumper settings table that I found that references j36 being used for anything. It won't kill the board, if I put an external 3V battery on there, will it?

I’d recommend against sticking random voltages on pins, probably won’t kill the board but might cause other issues.

If you have a multimeter you can check the resistance between the negative pin and a ground (should be 0 ohms) and the positive pin and either J11 pin 1 or pin 3, one of those two (should be pin 1 ideally) would be 0 ohms.

turbooo wrote on 2021-11-12, 21:06:

I’d recommend against sticking random voltages on pins, probably won’t kill the board but might cause other issues.

If you have a multimeter you can check the resistance between the negative pin and a ground (should be 0 ohms) and the positive pin and either J11 pin 1 or pin 3, one of those two (should be pin 1 ideally) would be 0 ohms.

I have a multimeter, but I have never been super proficient with it. I will definitely try it tomorrow, right now I'm scratching my head because I have an old asetec psu here with no fuse and the silkscreen value seems wrong. 250V T4AH which is a 4 Amp ceramic slow blow fuse. I thought all fuses on computer power supplies were fast blow? I have to clean it before I even think of replacing the fuse. It's full of dust and detritus. I will try your suggestion of checking if there is resistance between the pins. To confirm, I have to have a psu plugged in and running to test that, right?

To confirm, I have to have a psu plugged in and running to test that, right

Power supply needs to be turned OFF. As ground point I have used mounting screw holes or molex plug black wire.

Strictly speaking you can do it powered on but you’re much better off checking it with the power off so you don’t accidentally short something if your probe slips.

Okay! I have tested the pins with the power off. I think that the jumper information I found is not quite accurate. The listing for j11 shows that it is a 4 pin header. But the header for j11 on my board is only 3 pins. I checked all of the pins on j11 to the pins on j36 and did not get any sort of response. The multimeter just read 1. When checking the last pin on j36 and the ground plane it immediately dropped to 0.00 so there appears to be continuity there. But I don't know where the + pin goes to.

Hmm, okay that was my suspicion that there was something funny with the online jumper settings, they seem close but still off, as you’ve noted.

You can try this instead, check the resistance between pin 3 of J36 and the positive pin of the battery connector on the motherboard, that should read 0 ohms (remove the jumper for these measurements). Pin 2 and the same battery pin should read open circuit (i.e., 1), same for pin 1. If that is the case then you should be able to connect your external battery to pin 2 and a ground pin and I think that should do the trick.

Well, that was strange. I removed the jumper on j11 just in case, and then I tried as you suggested. I got nothing. It stayed on 1. I tried every other pin. Same result. Checked the negative side and the pin that has the negative symbol next to it on J36. Got a result there. So I took a picture of all of the jumper settings and removed all of the jumpers on the board. tried again. Nothing. No result on any pin. That shouldn't be possible, unless there's damage on the board, right? I guess I need to look really close on the board for trace damage.

It’s a little strange but let’s not panic just yet.

It seems the SIS 497 chip has an integrated RTC, so here’s one more thing to try: check whether any of the pins on J36 connect to pin 37 of the the 497 (you can see on the silkscreen that the right side of the bottom edge is pin 40 so work leftwards from there). Failing that, you can also check J11 and pin 37. Hopefully one of those will read 0 ohms.