Dell Precision Tower 7910 Power light comes on but fails to boot BIOS

There are a few revisions for that motherboard. the problem is that I'm not sure which one is the latest. (with this i mean that maybe one specific revision is having problems, while maybe the others are not)

Do you have a V3 or a V4 cpu ?

Very likely it will be hard to fit a standard motherboard inside that case, it's all a bit custom. You surely could keep the cpus, ram, cards, hdds to use in a suitable alternative mb ( supermicro by example ).. but hardly the case / psu

Thanks again for all the information. The processors are v3 here's the exact model:

Dual Intel Xeon Processor E5-2670 v3 (12C HT, 30MB Cache, 2.3GHz Turbo)

I think as I've already had the mb replaced by dell and the exact same problem happened 3months later I'm nervous about just replacing it again with the exact same md model from dell. 

My preferred route at this time is to rebuild the PC using a new case, fan, power supply & an alternative motherboard possibly one from supermicro. 

Any further advice or recommendations would be welcome. As I'm pretty new to building PCs from scratch here are the components I'm looking to reuse from my old system:

2 x Intel Xeon Processor E5-2670 v3 (12C HT, 30MB Cache, 2.3GHz Turbo)
64GB (8x8GB) 2133MHz DDR4 RDIMM ECC
2 x 2.5 inch 256GB SATA SSD
Nvidia Quadro K5200 8GB (2 DP, 2 DL-DVI-I) (2 DP to SL-DVI adapter)

Thinking about it maybe it's this separate board at the back that needs replacing. It's the board that the power supply plugs into. The power is then relayed from here to the MB.

Hi,

I brought a replacement motherboard off eBay it had been tested and as far as I'm aware is a working motherboard. I've installed it into my tower. Diligently replaced everything. One notable concern was that I found a loose screw that was wedged in between the case and the Power supply board this I can only imagine was left there accidentally by the dell technician that replaced my motherboard the first time. Anyway, I'm not pointing fingers at this stage I just want to get it fixed.

I ensured everything was plugged in correctly and powered up the system...

The exact same problem again. It seems to power up but then nothing no screen no bios nothing. I'm now thinking it could be a problem related to the Power supply?

Any feedback or advice is welcome. At this point, I'm wondering why I didn't just go the extra mile and build a non-dell rig out of the remaining parts.

it could be , or the psu. And I see that loose screw in the pic you posted... that's in a position it can short the psu

I'm sure by now you removed the wedged screw.

Dell Precision Tower 7910 Owner's Manual 

It can't hurt to try replacing the PSU card (that's what the power card is called), then the PSU if necessary.

Also, rarer I've seen PSU cards go out as compared to PSU's.  That wedged screw could've had an effect on the PSU card though.

Hi,

I'm on the hunt for a new PSU card no doubt I'll order one at some point this week. I've removed it and inspected it. to be fare it there are no signs of a major short? it looks a bit dusty but there are no burnt-out marks all the solder looks good. I've attached a couple of photos.

My suspicions now lie with the power supply. Could there be some kind of fuse or protection against blowing the MB within the PSU itself? Are there any ways to reset anything that might have tripped?

There's the small power test button on the backside of the psu

ah great, how do I use that button? Should I push it when the power is connected? Or is it just to drain the PSU of power when the cable is disconnected? 

With power connected and PC off, push the PSU test button.  If you get the  green light, it means 2 things, 1. all peripherals are good.  2.  PSU has power.  Green light when pushing test button doesn't necessarily mean the PSU is good.  A bad PSU can still spin the fans when test button is pushed.

If you don't get the green light, then it's disconnect peripherals one by one until you do get the green light.  This narrows it down if there's a bad peripheral.

I just bought one and am having this same issue and will likely just get a refund

Thanks for the post, I hope the refund goes ok. If you could ask where you purchased it from for an explanation of what went wrong that would be great. I assume if you bought it from Dell they would have some kind of report or someone would eventually restore it to its working order. 

Any information regarding what has gone wrong with it from the place you purchased it would be great.

Ok , lets recap :

you tried a different mb ( that was sold as tested working )

a new psu ( same as above )

Still have to doublecheck with a different gpu

Did you try with just one cpu installed ? 
With just some ram installed ?
with no dvd cable plugged ?