The LED speed display on AT cases is completely independent of the motherboards. If that also doesn't light up, it sounds like you have a PSU issue - or the front panel isn't hooked up properly.

In any event, it doesn't sound good. 200W is more than enough for just an So7 motherboard and VGA card, so if the 200W PSU is known-good, it one of the other bits that is at fault, most likely the motherboard.

One other possibility: you hooked up the P8 and P9 AT power connectors the wrong way round. The black wires need to be touching in the middle. Unfortunately, if you did so, it likely killed the motherboard even if it survived the death of the first PSU.

I hooked up the P8/P9 cables correctly with the blacks in the middle. Also, I think I may know at least why the turbo LED panel isn't doing anything. There's a header on the motherboard called "TB-LED," but I realized that's just for an LED that lights up when you press the turbo button and not related to the actual LED panel itself. The actual header cable for it, "TURBO SW," must of accidentally come loose and I have absolutely no idea where it goes on the motherboard at all. There's nowhere obviously marked for it. Same thing with the HDD LED and Power LED headers... Anyways, here's some pictures.

This is a full view of the motherboard:

The obvious header spots on the motherboard (there is no key lock on the case, so that's unused):

I have no idea where these are supposed to connect to:

This is the back of the front panel and shows the back of the LED display:

It'd be nice if someone could maybe identify the motherboard. That'd help the header situation. Once again, I'd greatly appreciate any help on this. Someday I should get around to posting a help guide on here (I have a method of getting Extreme Paintbrawl fully running on modern OSes). Thanks again.

Your board is a Dataexpert EXP8551

The LED display won't illuminate with just the 3-wire connector that comes from the Turbo button; this doesn't supply any voltage, it just tells the display if the button is pressed or not. There must be a 5V cable that connects to G and 5V pins on the display, on my AT cases this cable comes directly from one of the Molex connectors.

For troubleshooting your board, a POST diagnostic card is highly recommended. Also, some means to read the BIOS chip - it could be corrupted due to age.

You may also want to inspect the old PSU to find what failed in it. If that's a capacitor, then maybe it's not a big deal. If that's something else, that could be a big problem.

As for the bios, I think it was working : looking at the manual says it's a WinBIOS, and AMI's BIOS always do clicking sounds when counting the RAM

Ah, yeah. I see there's a two pin header that comes out of the old dead PSU, but that doesn't seem to exist on this known good test PSU I'm using. Oh well, guess the display just won't work for now...

I'll open the dead PSU soon and see what went wrong.

Also... if I never end up getting this motherboard to POST, I might look into getting something like a 286 motherboard to put in this case. Seems like a neat idea to me.

Well, here's the inside of the dead PSU and other than it being dirty, I don't see anything really that awful other than a slightly bulging capacitor. Probably shouldn't try using it again, though. I know after it popped there was a burning smell coming directly from the PSU. Also, the computer was actually still running even after the pop, fyi.

That capacitor on the last picture is probably bthe one that popped. I had one that popped on a 486 I bought. So far it didn't seem to have done anything bad

You're saying you're still using the same PSU after that happened to you or are you just saying it didn't damage the rest of the computer?

It didn't damage the rest of the computer. I'm planning to recap it though as the computer was still running after the blow up

Ah, okay. Well, I've continued to mess with it doing whatever I can think of and I still can't get it to even do anything on the monitor at all. Maybe I'll try reseating the socketed chips, but after that I don't know what else to do. Like I said, maybe it's best to just put another older motherboard in the case.

thepirategamerboy12 wrote:

...I have no idea where these are supposed to connect to: https://farm2.staticflickr.com/1942/44780664365_aa9987a3ee_o.jpg […]
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...I have no idea where these are supposed to connect to:

The power led is supposed to be connected to the 3 of 5 pins on the board labeled as "keylock". It should be either at the left or right side, not in the middle, So you need to check a total of 4 positions If you don't have the motherboard document. Turbo functionality in a socket 7 board is rare IIRC, but having a connector for thre turbo led, but not the switch is strange I think. There should be a HDD led connector, since your motherboard has on board IDE controller. Maybe you need to check near the IDE connectors.

If cpu and mobo alive it must "beep" if you turn it on with just cpu without any ram or add on cards and that would be sufficient to say mobo is 95% alive. Next, you may have dead RTC - ODIN (similar to dallas), in that case most boards don't post. Also white connector near CPU - i assume that is a socket for CPU VRM with some jumpers installed, if you CPU isn't early P5 with full 3.3V operation it may be also part of the problem (either already dead due to PSU, or not compatible without VRM). So you need to check voltages supplied to CPU first and RTC, before anyone could really help you.

You may want to buy a POST card to see if there's still activity on the bus, if CPU is being turned on, etc.

The keylock trick worked. The power led now lights up! Still doesn't do anything else, though. I took out the ODIN chip and it says on the mobo underneath it "DS12887A." I do have a spare DS1287A. Not sure if it works, but it's worth a shot.

I reseated all the chips and replaced the RTC chip, and still nothing. Took out all the RAM, too, and still not even a beep.

To get 5v you will need to splice 2 cables from the molex and connect positive to the 5v pin on the back of the led panel and ground to ground

Can't really contribute anything else on top what has been said about the board but not having the keyboard leds flash when you turn it on is not a good sign

Thanks for the diagram, and it isn't a good sign at all. I should test the video card in another computer soon to at least make sure that works.

thepirategamerboy12 wrote:

I reseated all the chips and replaced the RTC chip, and still nothing. Took out all the RAM, too, and still not even a beep.

Was it a new RTC chip?

Also one thing worth a shot is doing the CR2032 "dead-bug" mod on the old RTC. My Biostar MB-8500TVX-A had a dead RTC and the simple fix was exposing the + and - of the RTC and then soldering the CR2032 holder and popping in a new battery.