Technical question

[petrusbroder]

One of my computers does not start anymore. It has a Gigabyte mobo, socket 1156, with a i7-860, 8 GByte RAM. I've tested it w/o connected hard drives, with only one stick of RAM (2GBytes), GPU and Keyboard - the same symptoms as when fully equipped.
When I power up, it works OK for 2 - 3 seconds, then powers down and tries to restart.
Any guess what the problem may be? Mobo, CPU? I've inspected the mobo, don't see any broken capacitators or burned spots. PSU works perfectly, tried it in othe computer; also a brand new PSU does not change the behavior.
If it is the mobo, is it worth to get a "new" one (e.g. previously used)? Does anybody have one available for not too many USD (I pay for shipping) ...
If it is the CPU I will not replace it but use the parts for an other computer, the case; PSU, HDD, GPU, DVD-unit are all in good shape and much newer than the mobo, CPU and RAM.

The combo has worked 24/7/352 since December 2009 ... for almost 8 years, with less than 5 days rest during this whole time ... it has crunched all the BOINC-projects I've participaed in and all the Folding@Home races since 2009.

 

[crashtech]

I don't have any 1156 mobos or CPUs to assist in troubleshooting, that's what would be needed to rule out one or the other. I have had motherboards die almost as often as HDDs, it's the component I would suspect first. However, buying another 1156 mobo is likely throwing good money after bad, probably better to sell the i7-860 and move up at least a generation or three with an LGA 1155 or 1150 mobo that can likely use your existing RAM.

 

[iwajabitw]

Is the CMOS battery dead? Are you able to get in to Bios and diagnose?

 

[Markfw]

memory is what it sounds like to me. Is it DDR3 ?

 

[petrusbroder]

Is the CMOS battery dead? Are you able to get in to Bios and diagnose?

The CMOS-battery is good. Can't even get to BIOS.

 

[petrusbroder]

memory is what it sounds like to me. Is it DDR3 ?

Yes, it is. Have not checked it in an other computer ...
To me it sounds like something else, because I have 4 sticks of 2 GByte RAM and the same happens when i only have one stick of memory.
Also, there is no beep-signal (which comes when it boots and checks the GPU and RAM) when the computer first starts and then shuts down and restarts ...
I thought first it was the PSU (power delivery) since no beep-signal came - now I think it is something else.

 

[crashtech]

You essentially have spares of known-good memory, unless all four went bad at once. I presume you have already tried more than just one stick. That leaves the PSU, motherboard, or CPU. The PSU is less likely since the board fires up but fails to POST, but it's still possible, and a known good PSU could be tried as a last-ditch effort. Of the two remaining components, the motherboard is far more likely to be bad than the CPU, just based on my experience in fixing PCs. Finding someone with a spare 1156 mobo or CPU will unfortunately be an unlikely proposition.

Edit:
Some motherboards are picky about which memory slots are populated, so it's important to download a manual to determine the correct configuration.

 

[VirtualLarry]

Sounds like it might be detecting a CPU fan not spinning, and shutting down as a failsafe? Something to check, anyways, although I would think you would get BIOS alarm buzzes or continuous beeping, if the fan failed.

 

[petrusbroder]

Thanks for all your help.
It was not the CPU-fan being broken. it spins well.
It was not the PSU - i tried a totally new one which did not cure it.
The memory sticks were in the computer for at least 4 years - and working well before the crash. I have tried to use one stick after the other, so unless all 4 are broken the same way, it's not the RAM.
So: the mobo or the CPU. I don't know if I want to invest more time and effort into this - since both parts are due for change ...
I can get an new mobo (ASUS Prime 370-pro), a Rysen 5 1600X and 16Gbyte of DDR4 RAM for approx. 670 USD) incl. sales tax and shipment and that is not a bad cruncher/folder with a GTX1070 GPU.

 

[Markfw]

Sounds reasonable to me. That socket is dead. But since you are talking cruncher, an 1800X here used to be $299, but this am seems to have gone back up.
Oh, and how about the ASRock Taichi motherboard ? Its the best IMO

 

[StefanR5R]

If there is never going to be more than a single GPU in this PC, then a less pricey B350 board should be enough, right? Also, if it is meant to be a 24/7/35X cruncher again, overclocking is surely out of the question, and a board with top-end power delivery like the Taichi isn't really needed then.

Stepping up from Ryzen 5 to Ryzen 7 would cost at least € 90 more but may be worth it considering the extra 33 % cores for the PC...

Still, @crashtech has a point that money could be saved by going for an older platform on which the DDR3 RAM could be reused.

 

[iwajabitw]

One last check on that bios. Does it have an A&B switch in case the ueif/bios corrupted. Where you can switch to the backup and test. Or are you able to reset the cmos, hopefully.

 

[petrusbroder]

One last check on that bios. Does it have an A&B switch in case the ueif/bios corrupted. Where you can switch to the backup and test. Or are you able to reset the cmos, hopefully.

No resetting the BIOS to factory settings did not help ... that was the first action I took ...

 

[crashtech]

I thought a Haswell CPU would be a major step up while still being able to use the DDR3.

I have several 4C/8T systems that I'm looking to replace with higher core count Xeon systems, perhaps I could be of assistance.