Abit BH6 Mobo based system - Does not power on. Not power supply. What could it be?

[TangleWeb]

Greetings Gurus,

I am working on a slot 1 Abit BH6 (ATX) mobo based system. It is roughly 2-years old and has been working fine, no symptoms prior to failure. One morning it just failed to come on when the power button was pressed. Thinking it was the power supply, I replaced it with a new ATX power supply. Still nothing. On ONE occasion, I got a momentary light on the hard drive access led. This led me to believe it may be a bad switch. This is the type of switch that has 2 wires that run to 2 pins on the mobo. I figured shorting the wires would be the equivalent of the switch in the on position, so I cut off the switch and shorted the wires. Still nothing.

Questions:

1) Is shorting the switch wires the same as the switch in-line in the "on" position?
2) Is there a source of a new 2-wire switch (appears pretty standard) that terminates in the correct plastic jumper that would plug into the pins on the mobo? (This is a quality “Clone” Mid Tower case)
3) Can any of you think of other troubleshooting steps I have overlooked, or other comments\ideas?
4) I have a "Post Card" & a MultiMeter. I don't have much experience with the Post Reader, but I believe it will allow me to check for voltage at various points. Any ideas in this area?

Thanks all!

[Antimatter]

Try resoldering the power connectors on the underside of the mobo. There's a good possibilty of a dry solder joint.

[TangleWeb]

Antimatter,

You mean under the pins where the switch connects, or where the power supply connector attaches to the board?

[Antimatter]

Power supply connector. Do the voltage regulator connections while you're at it.

Ruslan would be the one to ask about how to test for bad regulators when there's no power. I'm sure my half baked system of loose wires isn't much good for manufacture!

[Sorry_I_Win]

Most atx power switches are a momentry on/off switch. To turn on, simply touch the wires together and then open the connection again. If you leave the wires shorted together, the machine will most likely shutdown after 3-5 seconds.

As far as the dead mobo is concerned, I was going to recommend checking the clear cmos jumper if it was a new system, but since it has been working fine for you, that most likely is not the cause.

Have you tried removing all cards but the video. I have seen this happen with a bad card (fried modem.. etc). Also make sure video card, ram, and cpu are firmly connected. May even want to remove and reinsert them to get a better contact.

Hope this helps.

[markoliver]

I've also got a BH6 that's about 2 1/2 years old. Sometimes after playing around inside the case swapping parts mine won't power up either. Quick blip on the led on the front and that's it. After I unplug the ATX connector a few times and unplug from the wall it will mysteriously boot and I won't have another problem until the next time.

[BarnesConsult]

I had a similar problem with a BE6-II board. I bought one that arrive DOA. I got a replacement and used it for about a year. Put it in the attic for a couple of months, took it back out, and nothing. I tried a different PS, (both were good), I tried a PCI video card, ISA video card, nothing worked. I tried different memory, booting with no cards, nothing. I figure it's just dead!

[Sorry_I_Win]

Yeah... I think it's official now.... Abit is on my do not buy list. They seem to always die after a year or two.

[tiffin_tom]

Two things that sometimes get overlooked when a system is not booting:

1) reset switch is stuck in the reset position

2) if the system has a keylock, make sure the keyboard is not locked.

[TangleWeb]

I really appreciate all of your responses!

I have been slammed at work & little time at home, so have not had a chance to try some of the suggestions here. Today is the day! I'm going to do the following, in this order;

1) Remove all cards except the video. Unplug the reset switch from the mobo in case it's stuck "on". Check the clear CMOS jumper for correct position.

2) Try a different ATX power supply.... Just in case the replacement was bad also. Check the solder connections as indicated above.

3) Install the Post Card Reader & check voltages, if any.

4) Check prices on www.pricewatch.com for a new slot 1 mobo that will support the PII 450 Processor in this system.

5) I may try the processor in another slot one system I have available to verify that it's good.

I will let you all know of my results.

Thanks again for any & all input & feel free to comment further.

[orange]

I would remove the vid card too, it isn't needed to see if the system will switch on, although obviously it won't post. I've had a bad vid card cause this and also a dodgy CDROM, any short circuits in the system and the ATX PSU won't power up. Basically remove and disconnect everything bar the CPU and a single stick of memory - short the soft power pins with a screwdriver to fire it up. Also try taking the board out of the case, could be something between it and the backplane...

[TangleWeb]

OK, here's the latest update....

Orange, I had the same thought about removing the vid. I tried a third ATX power supply, removed the mobo from the case, the slot 1 450 from the mobo & re-seated it. I re-installed the mobo in the case, left the vid out (no cards at all), shorted the soft power pins.......

Nada..... Nothing.....

So.... With the clients OK, I am ordering an Abit VA6 (I like Abit boards, despite this problem. I've used a bunch of them & had few problems.) for $76.95, an Intel PIII 750 MHz Slot 1 processor for $120.95 (OEM, full 1-year dealer warranty though) & an Enlight 300W ATX Power Supply for $27.95. All from Axion Technologies http://www.axiontech.com/index3.asp This will definately solve her problem! She may want to spend an additional $70 to go to an Intel PIII 850, I'll give her the option.