ux-3 wrote:

I just found a working 486. It has opti chipset, 1 MB Tseng ET4000 ISA graphics, 4MB, 200 MB HDD, two floppy drives, AMD 486DX 4 […]
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I just found a working 486. It has opti chipset, 1 MB Tseng ET4000 ISA graphics, 4MB, 200 MB HDD, two floppy drives, AMD 486DX 40 MHz. Two Slots have an extension, I assume VLB. It booted and when I typed win, it started win 3.11.
Win 3.11 looks incredibly cool and sharp on a 15" TFT.

Problems: I have no serial mouse. And the onboard rechargable battery leaked heavily. So I need to get rid of it and find some replacement. It is a little barrel with 3.6V and 60 mAh. I hope corrosion is not too bad already.

Would it be possible to swap the cpu for any other 486, like Intel DX2/66?

First thing you'll need to do (except for removing that battery and cleaning up the mess it left!) is finding a manual for it

Edit: chances are good it'll support the 5V dx2 chips 😉

ux-3 wrote:

Would it be possible to swap the cpu for any other 486, like Intel DX2/66?

Depends on the board, but most 486DX2 chips should work fine. If you want to take advantage of the 40 MHz bus, I'd recommend an AMD 486DX2-80.

4 MB RAM is a bit low for a system like this, consider at least double the amount. Back in the days many pre-built systems were notoriously low on RAM - consumers tended to buy machines with a high MHz count and RAM was expensive.

The thing has 4 banks still empty and I still have plenty of 30 pin ram here. I will try 8 MB eventually. For the manual I need to take the board out and find the model I've got. The case is rather small, so I do that when I have more time.

The HDD is a bit loud. I wonder if I can but in a 6GB HDD and use at least 2GB.

What should I replace the battery with? I first thought to solder in two alkalines, but they won't like to be charged.

I identified the board: It is A Shuttle Hot 409 V2.2
500 MB max HD size unless I can get the new bios on a chip.
Sounds like a good choice. I guess I can ran the DX40 as DX33 too.

Is there a performance difference between AMD and Intel?

Use a drive overlay software like Ontrack Disk Manager then you can use a bigger hdd

The battery will be the first issue. There is a jumper for internal/external battery. But how does it work? If I switch to external battery, where would I connect it?

ux-3 wrote:

500 MB max HD size unless I can get the new bios on a chip.

There are some ISA cards that have an updated IDE bios on board that would support larger HDs.
I'm not sure but 2GB may be the limit, or at least on my Promise EIDE Max it was.

There is a jumper for internal/external battery. But how does it work? If I switch to external battery, where would I connect it?

The outer two pins are for the battery, usually there's a jumper on the middle two, which, when removed, disables the onboard one (which you'll be removing anyway). As for polarity, just take a multimeter and check which of the outer two pins is connected to ground, then the other one will be for the positive lead.

For the IDE, I'd recommend going for a VLB controller. Heres a nice cheap PIO4 EIDE card with a BIOS that supports 8.4GB drives.

Also, while you're at it, a good accelerated VLB video card would be a nice addition, if you're going to be running Windows.

Old Thrashbarg wrote:

.....As for polarity, just take a multimeter and check which of the outer two pins is connected to ground, then the other one will be for the positive lead......

Sorry for asking such a noob question, but you'll have to measure the ground while the system is on, right?

Btw, would it be possible to make your own external battery packs? You'll need 2 standard batteries, right?

No, ground is ground, regardless of whether the computer is on. Actually, ideally you'd have the computer turned off and unplugged when prodding around at it.

As for making a battery pack, yeah, you can, just a small AA/AAA holder and a couple wires... hook the batteries in series, and make sure you get the polarity right. You might need more than two batteries, though. 3V will work on some boards, and I'd try it first, see if it'll save settings with that much, but more often they needed ~4.5V.

Somebody on here told me that if you turn the PSU off, it's still grounded as long as it's plugged in. The switch doesn't cut the ground off, apparently. So it's probably best to leave it plugged in but PSU switched off?

Yes, it would still be grounded as long it's plugged in, and that would probably be the safest solution for an ATX system, but I would never do that on an AT system, where even with the thing turned off you still have line voltage going to the (often not very well insulated) power switch in the case. One screw drops in the wrong place, and you've got major problems.

And anyway, static discharge can be adequately prevented simply by keeping your body and the computer at the same electric potential... i.e., touching a metal desk leg or whatever to [mostly] ground yourself, then clipping your antistatic wristband doodad to the bare metal of the case.

Oh yeah that's right. The AT PSU has that hot wire going through the case all the way to the front switch. The connection at the switch in my case is essentially non-insulated by design, with the metal screws the wire runs to being nice and available to fingers. I've felt 120v once or twice there. Works better than caffeine for sure. 😀

Old Thrashbarg merely suggests to find out which battery connector is internally directly connected to the "ground" of the MB - which is connected to the center black leads of the power connectors. I will check that with the board still build out.
Yesterday, I thought about VLB graphics and when I looked it up, there were 5 cards on ebay here, one ending 11 minutes later, with no bid yet. So I was giving that one a new home. Comes with three booklets and disks. CAD capable card, S3 chipset, I think.

Old Thrashbarg wrote:

Yes, it would still be grounded as long it's plugged in, and that would probably be the safest solution for an ATX system, but I would never do that on an AT system, where even with the thing turned off you still have line voltage going to the (often not very well insulated) power switch in the case. One screw drops in the wrong place, and you've got major problems.

And anyway, static discharge can be adequately prevented simply by keeping your body and the computer at the same electric potential... i.e., touching a metal desk leg or whatever to [mostly] ground yourself, then clipping your antistatic wristband doodad to the bare metal of the case.

I'd unplug an ATX board always when working on it. I fried a board once even though the switch on the ATX PSU was set to "0". Fried something near the bios (battery) instantly

I've actually fried my P3B-F by accident too. Lots of smoke... After that, it was dead. I found the fused layout track and replaced it with a wire. I was lucky, it works again. If not, ebay spits them out at a comfortable rate.

I just tried out the documentation. 25 MHz are easily selected with a single jumper. I still have to test the turbo switch. If that works, there would be no need to externalize the jumper.

So, I removed the NiMH Battery and rinsed the board clean. It does still boot, but rightfully complains that the CMOS battery is low. Old Thrashbarg's assumption is right: There is a 4 pin Jumper, with pins 2&3 closed for onboard battery - which is gone. I can't use the battery holes to solder in leads for an external one, cause the board will charge them. I have to do it via external battery connector.

Only pin 4 connects to ground. So would I connect + to pin 1 and - to the ground and remove the jumper?

Battery issue solved:

Now I need help with the multi-controller.
It has an FCC of:
ID2-W83757S
The jumper rows involved are JP2, JP4 and JP3.
Any one here has infos on it?