HP DC 7600 (Small Form Factor) Will not power up - motherboad and ethernet lights on

[timez]

Hi,

 

I am usually very good with computers - but this one has me baffled.

 

I have a HP DC 7600 - Small Form Factor - Desktop PC (me and my friend were fixing it up for another friend)

 

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It was working fine - and although i had reports from the last owner it cut out a lot - the last time i worked on it about a week ago - for about 6 hours straight - it didnt cut out once.

 

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Today (a week later) I turn it on - it boots normally - goes into windows - and i started a check for windows updates.

 

Than all of a sudden (after about 2 minutes) - It just switches off without warning.

 

(This happend at the exact same time i switched a laptop on at the wall (in a totally different socket)) - I think its just a conicendece - but thought i better say in case.

 

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I have a power light on the motherboard that is on (Green) - and also the ethernet port lights work fine (Green / Orange) - it just wont switch on.

 

At first - when pressing or holding the power button - the hard drive light on the front panel would light up (Green) - until i released the switch.

 

I then did a power drain - unplug - hold power button for at least 20 seconds - plug back in.

 

 

...Since doing that - I have no lights come on at the front when pressing or holding the power button...

 

Oh ok - since leaving it plugged in for about 10 mins without keep trying the power switch - that hard drive light at the front now comes ON again, when pressing or holding the power button - Still won't turn the PC on though.

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Things I have Tried:

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* Making sure all power connectors inside the case are seated properlly (and all the data cables too for good messure)

 

* Leaving the power cable out / in for a while before trying again

 

* Reseating the RAM (I would have done the CPU - but that thing is in there very solid - no way it could have moved on its own)

 

* Shorting out the 2 pins for the power switch on the motherboard

 

* Reseting the CMOS

 

* Jump start test of PSU (Green to Black wire) - with a load - The Power Supply came on fine - on it own - Soon as its connected to the PC again - same problem.

 

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None of this worked - execpt the PSU test - but as i say - PC still will not switch on.

 

I have NO other lights / beeps for warnings just...

 

Ethernet Lights = on (Green / Orange)

 

Motherboard Light = on (Green)

 

Hard Drive Light = on (Green) - when power switch is depressed only

 

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I really hope someone can help me with this - as im out of ideas...

 

Sorry for such a long post - and thank you if you read it all.

 

And thank you in advance for any help you may give.

 

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Timez

[Plastic Nev]

Hi and welcome to Extreme Tech Support - Free PC Help.

Daft as it may sound, it could still be a power supply fault as you only get those lights you mention and no fans.

The only real way is another known to be OK power supply.

If however a different power supply still has the same result, then it may be the motherboard itself.

Try either another power supply, or that power supply in a different computer if possible first, and let us know the result.

 

Nev.

[timez]

Is it possible to use a full size ATX PSU on a Small Form Factor PC?

 

Not permantally of course (as it would not fit in the case)

 

But just to test it?

 

I.E. - Will the 20/24 pin motherboard connector from the full size PSU physiclly fit the motherboard header?

 

Thank you.

 

Timez

[BreatGritain]

Hi Timez, yes a normal atx PSU will work for testing

[timez]

Oh excilent - My friend will be pleased to know we can at least test it :)

 

I will let you know the results tommorow.

 

Thank you.

 

Timez

[timez]

I did try the full size ATX PSU to test it,

 

But the connector did not fit the header on the motherboard - was way too small for the full size 20 Pin connector.

 

Gonna have to just buy a SSF PSU to test with?

 

Timez

[Plastic Nev]

Hi just looked this problem up, it does seem that the SFF motherboards have a smaller connector, is it eight pin or other? I was hoping I could find an adapter for you but there doesn't look like there is one.

Hope someone else can come up with other idea's.

 

Nev.

[BreatGritain]

I apologise.

 

I've broke down a few Shuttle XPC SFF computers and the PSUs from these were interchangeable with normal ATX ones, I assumed it would be the same theory.

[timez]

Thats ok - my friend says we will buy the power supply and if it still doesnt work - we will keep the PSU as a spare for future use on other PCs of that size. - When we get the new one and try it - i will let you know the results. - It may be a week or two.

 

Timez

[timez]

Ok I saw him today and he said - rather than buying a PSU and it possibly still not work...

 

he asked is there an adapter you can get to test it with a normal one.

 

It looks that the 24 pin ATX to HP Mini ATX adapter does exist.

 

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However...

 

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as you know - most boards use a 4 pin CPU extra connector - so far so good...

 

 

The HP DC-7600 does not...

 

It has a 6 pin connector (and i very much doubt the 6 pin PCI-Express connector is going to work or even fit this.

 

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Do you think there is any chance of an adapter for this existing as well somewhere?

 

I know i could probeblly get a multi-meter and see what voltage is supposed to come out of the old PSU pins for this - and cut and splice a working standard ATX PSU 6 pin PCI-EX connector to do the same - but the plastic may not fit - i have not tried yet.

 

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Its fine if i can just cut and splice the working PSU - and test with that + the adapter for the 24 pin connector.

 

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I really do not want to have to cut and splice the actual HP SFF PSU - as my friend will not be happy at all with that.

 

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Is that my only option though if the physical block of the standard PSU PCI-EX does not fit on the motherboards 6 pin connector?

 

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I realise thats all very confusing to read - but what i basiclly mean is - If it came to it - i could cut the real 6 pin block off the HP PSU - and splice it with the known working standard PSU after testing what voltage should be coming out of that.

 

But my friend and me wont be happy - because if it wasnt the HP PSU thats gone - we have cut it and would have to splice it back together - and if it is working would want it in tact.

 

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So my main question is - does anyone know of an adapter or anything i could use instead? so it would be - ATX 4 pin CPU power to HP propority 6 pin motherboard header.

 

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Thank you

 

Timez