P870DM-G won't POST

Hoping for some ideas, as I am stumped.

I purchased a used P870DM and it finally arrived (postage delays are no joke at the moment).

The system came with a CPU (unsure what model as the liquid metal ate away the writing on the lid), 980m, 16G ram stick and no HDD.


When it arrived yesterday, I was excited to get it powered on and see what bios it would have had etc.

However it wouldn't pass POST, just stuck in a loop of turning on and off.

I figured it could be bad ram, as I never heard of the brand. Lucky I had 2 spare sticks of 2100mhz DDR4.
That didn't seem to help.

Next I figured maybe the 980m had given out, so to test that I pulled the 980m and installed it into my P375SM, it works fine in that machine.

Also I took the known good 870m from my P375SM and installed it in the P870DM, still no luck.

I already had a spare motherboard sitting aside (thanks to the marketplace here), that also already had a Dsanke bios flashed onto it.

I figured I would rule out the motherboard and CPU at the same time, by swapping to my spare board along with an Intel i5-8600.

Finally I got to see the bios screen!
I was relieved, however when exited the bios and restarted, the issue returned ...

Now I have tried swapping all the components back. I tried flashing the dsanke bios onto the original motherboard that came with the machine and tried my 8600 there, even tried an i5-7400.

My spare motherboard was already modded to suit a 1070, so I tried that combination too (the 1070 had a GOP updated vbios as required).

Still nothing seems to work.

The only parts I haven't changed yet would be the screen (which I know works because the machine booted into the bios one time), the power button board, audio board and touchpad board .

I'm hesitant to start ordering those daughter boards I(guess they'd be called that), because again the machine did reach the bios page once.

And finally the keyboard, don't have a spare but also if I leave this one disconnected, still get the same issue.

Wondering if anyone can think of what else I should try. I'll take a break from troubleshooting this until the weekend.

 

The link below has some different BIOS's versions and one vBIOS., try them and see what you can get:
https://1drv.ms/u/s!AiLKbEJ_isKEiuAU2iyKDIpj62U4pg?e=VJlLsJ

Try as well to focus on the G-Sync GPU/ Screen issue they must match.

There is a % possibility that you have malfunction 2 motherboards.

Good luck.

 

Appreciate the reply , thankyou.

It appears I have got the machine to POST now with the original parts (plus the dsanke bios) and the i5 8600.

Not sure what caused the issue, funny that it did POST once with the spare motherboard.

I'd like to think it was something to do with the way the CPU sits in the socket when pins are taped .

However that doesn't explain why it wouldn't POST with the stock bios and whatever CPU came with it (still unsure what this is, likely an i3 of some kind).

Won't be messing with the system any further just yet while it's working.

 

Good NEWS, congratulations.

 

Could be socket retention, i'd check for a bad pin.

 

After contacting the seller I now know why it didn't pass POST with the cpu that it came with, it was a dead 6700k used as a dummy cpu to protect the socket during shipping.

I also believe my i5-7400 is a dud.

The i5-8600 has been running nicely though, at 4.3ghz with 102.5mhz bclk and some tweaking of power limits.

Now I need to source another stick of ram as running in single channel isn't great. And a new ssd. Might even do a TM cpu heatsink if one comes up at a good price.

 

Be careful though, even if you get exact same stick they aren't pretested as a kit of two. So you might run into some issues with subtimings differing a little and affect stability.

 

That depends on the speed, slower sticks are unlikely to care much.

 

Good point, 2400/2666 might not care that much but it's something to keep in mind.

 

glad it all worked out i have a few of them and some of the most confusing issues come from damaged flex cable connectors always check them ( in my experience as there are many that can go wrong on the DM<3 )