Dead M91p. Recovery possible?

[Garlic Bread]

Hi.

I recently acquired a Thinkcentre M91p which worked when I picked it up, but as I was installing WinXP the display output from the iGPU suddenly died and the system became unresponsive. I tried to insert a couple of dGPUs that I know to work (a Radeon HD 7570 and a R7 250), but neither gave a display output. During my testing I got two short beeps on boot which according to the manual is a CMOS error, but without being able to see what happens on screen I can't really do anything about it. I tried changing the CMOS battery, I activated the CMOS reset jumper, and I swapped the existing i5-2400 for an i7-2600 just in case that the iGPU was at fault. Nothing gave me the display output back, but the CPU swap ended the CMOS error beeps for some reason.

Have you got any idea what might fix the issue? I have an unused M92p mobo in my pile of spare parts which I assume would fix the error, but I would like to salvage the original mobo if possible.

[RealBlackStuff]

Blown fuse(s)?

[Garlic Bread]

I should not have said that the system became unresponsive, because the fans and LEDs still come on when I press the start button.

Where is the fuses located? The manual does not mention them, but it would make sense if the fuses was not meant to be a serviceable part.

[RealBlackStuff]

Try and get the schematics for it.
On the mobo fuses are (usually) marked as F1, F2, F3 etc. and often you also find their value printed nearby.
Use a multimeter to check those fuses for Continuity.
If blown, piggyback-solder a new one on top of the old one.

[axur-delmeria]

Have you checked if the RAM is good? Bad RAM can cause lots of weird stuff to happen.

[Garlic Bread]

No blown fuses detected.

I had not checked the RAM but I just did. I had 4x4GB of DDR3-12800U installed, which is faster than what the system support. When I installed it I thought that the RAM would just run as slow as the memory controller dictated, but now that I think about it this might not have been so. Anyway I tried installing a single stick of DDR3-10600U that I know to be good and the two short beeps on boot is back, but there is still no display output from either the iGPU or any of my Radeon dGPUs.