I seem to have just lost the crunching use of my QX6,700 quad, using XP Pro (32 bit) at 3.1GHz.

We had a power dip which affected this PC, but not the Penny or the Xeon Prestonia or P3.

During trials to reboot, I proved that 2 power cords for my quads had gone at the same time. Neither would power the Prestonia. But, fortunately, I found 2 more (one never used) and the newer quad is back up crunching.

No matter what I do with the live power cords to the older quad it will not come on. Zilch, Nada, Kaput, dead.

I can only assume the PC has blown a fuse (say on the power block - it is a 450 Watt one) or the MoBo is gone or it's something else.

Can anyone guide me where the fuses are to be found beyond the power cord fused plug (which is OK), and what are they rated at?

For example, is there a fuse in the PC power pack? Are there other small fuses I need to be aware of.

The MoBo is an Asus P5B, and when it is running RealTemp 2.60 says the cores are at 58C, 58C, 57C, 57C and steady.

I am hoping it is just a fuse which needs replacing, and not more serious.

You can find the pinouts here. If you can get access to a volt meter, you can tell if it is the power supply. Whether the PS has a fuse or not depends on the power supply.

Based on the fact the the power cords both went at the same time, I suspect it was a major overvolt event and not a power dip.

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BOINC WIKI

Thanks John

I think I will have to wait until Monday to get at test kit. But, from feedback I suspect the PSU has gone and will need to be replaced. Hopefully, nothing else will be found wrong.

Easiest method to test, grab a DMM, turn on PC and remove the mobo powersupply.. check your PSU PIN out schematic and confirm the required voltage output, since its all TTL.. set the DMM to the appropiate scale of measurement.

Hopefully its your PSU.. although Im a little concerned with the size, 450W... seems kinda low, id like to know your hardware specs (GPU, mobo.. etc)

-cheers

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If the problem is a blown fuse, you will have to open the PSU. The cases for these are two U-shaped metal covers that mate one into the other. There are eight small screws that must be removed to open them up. Once you open it you can look inside. Most of the time the fuses will be soldered in pigtails but once in a while they will be a plug in glass cartridge. You must replace with an identical type, not only in their current rating but also they usually are slo-blow.

If the fuse is soldered in it can be removed with a soldering iron but make sure you heat sink the leads otherwise the heat from desoldering may melt the fuse element. Unless you have experience with a soldering iron, I would buy a new PSU and don't try to replace the fuse.

AND NOW A WARNING. THE FILTER CAPACITORS ARE CAPABLE OF KEEPING A VERY LARGE AND SOMEWHAT DANGEROUS CHARGE. YOU MAY HURT YOURSELF OR THE COMPONENTS INSIDE IF YOU SHORT THEM. IF YOU HAVE NEVER SERVICED ONE OF THESE THEN JUST BUY A NEW ONE AND DON'T MESS WITH THIS ONE.

Make sure you put the case back in the original way and don't crimp any leads when you reclose the case.

Easiest method to test, grab a DMM, turn on PC and remove the mobo powersupply.. check your PSU PIN out schematic and confirm the required voltage output, since its all TTL.. set the DMM to the appropiate scale of measurement.

Hopefully its your PSU.. although Im a little concerned with the size, 450W... seems kinda low, id like to know your hardware specs (GPU, mobo.. etc)

-cheers

A quick note on this technique. The PS won't put out the listed voltages unless the "PS_ON" pin connector is grounded. This is usually used by the power switch circuitry to control your power to the CPU etc...

A good way to check if all the required signals are correct is to monitor the PS_OK pin connector. This signal is raised when the PS says all the voltages are correct.

So you can't just disconnect the cable from the motherboard, turn on the PS, and expect to get voltage on each pin.

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Mark

hey computer guy thanks for adding that... glad to know someone caught a VITAL piece of information I forgot to add :P

"high five"

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Easiest method to test, grab a DMM, turn on PC and remove the mobo powersupply.. check your PSU PIN out schematic and confirm the required voltage output, since its all TTL.. set the DMM to the appropiate scale of measurement.

Hopefully its your PSU.. although Im a little concerned with the size, 450W... seems kinda low, id like to know your hardware specs (GPU, mobo.. etc)

-cheers

A quick note on this technique. The PS won't put out the listed voltages unless the "PS_ON" pin connector is grounded. This is usually used by the power switch circuitry to control your power to the CPU etc...

A good way to check if all the required signals are correct is to monitor the PS_OK pin connector. This signal is raised when the PS says all the voltages are correct.

So you can't just disconnect the cable from the motherboard, turn on the PS, and expect to get voltage on each pin.

That's the Green to Black wires.

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The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's

Soon to be able to find out what the problem is, now it's Monday, etc.

Tests show the only damage to the quad was the PSU.

Now waiting for a 580W higher build quality more robust PSU to be delivered.

I hope to have the rig back crunching late tomorrow afternoon or Thursday am. It will be targetted to Einstein first.

could u do me a favour, im rather curious as to your hardware specs?

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could u do me a favour, im rather curious as to your hardware specs?

This should give you a clue, and it runs much faster than stock