Help determining dead mobo vs CPU

[smashguy37]

Running a Core 2 Quad on an ASUS P5Q board. Was having random freezing, narrowed it down to a stick of RAM. Removed it to run on 2gb. Installed new RAM (2x2gb) and then tried to incorporate the one old stick of RAM that still worked and my computer worked for 10 seconds and booted then turned off.

Started removing components and read through the tests posted here and bread boarding (which is what I normally do).

Thought my PSU was dead (Seasonic) so I got an old backup one out. I know it works - I used it a few months ago to troubleshoot my aunts computer. Realized neither work if the ATX 12v is plugged in, but both will run the lights and fan if its unplugged.

I took my Zalman cooler off and cleaned up dust build up around the CPU as well. My system does not have a speaker but I hooked my old case speaker to the plug but haven't heard a single beep this whole time. Can anyone wager a guess if the mobo and or CPU is dead? I'm confident it's not the PSU but I wish it was. I'm hesitant to replace anything because I would basically have to replace most my system as getting Core 2 boards and CPU's seem scarce now with the i7's, etc.

Thanks.

 

[clutchc]

If the system 'tries to start' with the CPU power unplugged only, you are right to assume it is either the board or the processor. I would assume the board first, because that is the usual suspect. Especially with no beep. CPUs can die too, but it is much more rare. Could you have damaged something by pressing in on the RAM sockets too hard? Cracked a solder trace?

Trying a known good CPU is the only thing I can think of to be sure. Or the CPU in a different board. Maybe try removing/replacing the processor.

 

[Fire2251]

Sorry I don't know how to determine MB or CPU is bad without swapping the part. According to ASUS web site P5Q MB can take very old CPU like Pentium 4, Pentium D, or dual core 2140. If there is no other way, you can try to buy the cheapest CPU about $2 on ebay to test your MB.

 

[clutchc]

+1^
Of course you'll always wonder if the CPU you bought was any good or if you got snookered. But it's an idea.

 

[smashguy37]

I have been sitting here wishing I had extra compatible boards and chips completely forgetting about my Pentium D! It's been so long since I've had to fiddle with this stuff I forgot.

Unfortunately, I swapped out the CPU's and the board does the exact same thing - the first button push a quite flash of green LED from my fan and then nothing. The fan runs normal and then a few seconds in it goes to full power (without the ATX12v).

I think - maybe - the store I use has a compatible Gigabyte board (one model only) but I fear replacing that and still having problems and then I wonder why this happened when I was dealing with the RAM - although a lot of failures I've had in the past or helped people with, sometimes two components to at once. The solder joints and everything looks good to my eye, I don't see anything out of the ordinary.

I would assume at this stage it's the motherboard? I'm 90 percent sure the Pentium D CPU is fine..I had to stop and wonder why I replaced it, but I think it that was a motherboard issue (and upgraded while at it). Any other thoughts are appreciated, thanks for the help so far guys.

 

[clutchc]

I feel (sitting here far away) that you found the problem. That is a quite old board. Caps dry out and fail. VRs can surge. Etc. Maybe now's the time to do a complete upgrade. Haswell? Ivy Bridge? AMD Vishera?

 

[smashguy37]

Normally I would, I tend to use systems until they fail (sadly, since I have been building my own systems this one at 4 years lasted the longest). I remember I bought the CPU right before the i7's came out..probably should have waited.

I was hoping to hold off because I shouldn't be throwing money at this stuff right now, but I was afraid of this because even though I liked the Q9550 the board dies and I'm SOL. Now even the RAM I just bought would have to be taken back. You're right, I guess the LGA775 is a dinosaur now and judging from searching online, barely exists. 4 years flies!!

Maybe it isn't appropriate here, but could you suggest some mobo/CPU combos? I don't want to go super high end but I'd like to have it last - i7 I guess. I don't do gaming, but I work as a videographer and while this isn't my work computer per se I edit a lot of photos on it and edit the occasional video with it.

Is it likely I would have to replace my Zalman fan? Don't remember how compatible these things are with different architecture (if at all). Thanks.

 

[clutchc]

If finances are such that a new PC is an extravagance right now, look into finding a used 775 board on an auction site like ebay. Look for sellers that have 100% feedback (or close) and have sold a number of items. I have had to find older components myself, and haven't yet been 'screwed' by any of the sellers. Look for those that allow for returns.