Question Faulty motherboard or CPU

[Scottyp123]

Hi, I am looking at a mates PC that has gone faulty, problem is there isn't any HDMI output, either on the board or from the GPU.

What I have tried up to now is disconnecting everything of the board and took the memory out so the only things connected to the motherboard are the power supply and the cpu fan, (GPU removed as well). The motherboard powers up and the fan spins but there is zero output from the on board HDMI slot. It wont even show a bios/boot screen, its as if the HDMI is unplugged.

I have tried putting the GPU back in but there is still zero output from either the GPU or onboard

I have swapped the power supply for a known good one, the HDMI lead is good as is the TV.

I have removed and re-seated the CPU, no bent pins or anything.

I have tried doing a CMOS reset. I have now taken the battery out for a bit to see if that does anything.

The motherboard is an AS Rock z370M Pro4 and the CPU is an i7 8700k.

I know it must be one or the other but which is more likely, the nearest other PC that I could try swapping the CPU with is a G4560 pentium but thats kabby lake and the i7 is coffee lake and I'm not too sure if they are compatible, will one CPU work in the other socket?

Edit :- I'm just looking at compatibility and maybe the g4560 will work in the coffee lake (faulty?) motherboard to test it, does that sound right before I blow them both up?

 

[Gam3r01]

You say the HDMI and TV are good, how did you confirm this?

 

[Bob O' Goobo]

Put the memory back in. You will not get video output with the RAM out.

 

[Scottyp123]

You say the HDMI and TV are good, how did you confirm this?

Because its the tv and lead I'm currently using to type this and the reason he brought the PC to me was no video output so its unlikely both TV's/leads would be faulty/incmpatible.

 

[Scottyp123]

Put the memory back in. You will not get video output with the RAM out.

Really, not even a post screen to tell you the memory is missing?

 

[Scottyp123]

Really, not even a post screen to tell you the memory is missing?

To quote myself, yes you need the memory in to get a video output. Thanks to Bob it's now booting up into windows again. there was a dodgy pin on one of the ram sticks, a bit of dirt or something maybe and at first with two sticks in it wouldn't boot. So I gave it a bit of a scrape and it now seems to be working ok again. I suppose its possible that removing the battery fixed it but I think it was much more likely the memory.


Thanks Bob.

 

[Bob O' Goobo]

To quote myself, yes you need the memory in to get a video output. Thanks to Bob it's now booting up into windows again. there was a dodgy pin on one of the ram sticks, a bit of dirt or something maybe and at first with two sticks in it wouldn't boot. So I gave it a bit of a scrape and it now seems to be working ok again. I suppose its possible that removing the battery fixed it but I think it was much more likely the memory.


Thanks Bob.

Yep. I had a similar problem with brand new RAM sticks not being seated and PC not posting. I blame it on these newer motherboards with the RAM slots with only one locking lever at one end. You engage one end into the tab and rock it into place and lock the lever at the other end. Because of this I didn't get proper seating. Thought I had bad ram until I figured this out. I hate em.