P170EM black screen, no POST

My P170EM this evening refused to POST. Just a black screen, backlight not coming on the display panel but the backlight on the keyboard came on, and the whole thing shuts off after about 15 seconds.

I tried removing the RAM and drives, same behaviour. When I removed the CPU it refused to do even less. When the GPU was removed the fans spun on max then it shut off again like before. No beeping of any kind.

I upgraded the 680M to a 980M in 2015, got it from eBay but the seller was from NBR. I don't have the 680M any more or that would have been the first thing I swapped out.

Does anyone have any ideas as to what else I can test to try to narrow down the problem?

 

Removing the 980M it should still boot into windoze if there was no other problem, tho it'd be beeping and would shut off after a minute

Try clearing bios settings/ec, remove all power sources including CMOS battery backup, hold power button 20sec, wait 10min, boot it back up

 

I pulled the battery and CMOS battery like suggested, but it exhibits the same behaviour as before. Could it be the motherboard?

 

Look up a no POST troubleshooting checklist that'll have everything listed to try in a logical order rather than me suggesting stuff OTOH

I've had my P170EM go into a no post for whatever reason a couple of times. Random things seemed to bring it back, like moving ram sticks around or pulling it to bits and cleaning every speck of dust, nothing I could ever point to or reproduce.

Thing is unless you have another unit to test your RAM and CPU are ok on you can never be sure they're 100%. Ram you can check one stick at a time in different slots. Then try a disassembly and check of all connectors and inspect for physical damage, scorch marks breaks in solder, wobbly bits that shouldnt be wobbly etc

 

With your components in, do you get anything on an external display?