Question PC turning off and won't boot at all, possible PSU or motherboard issue?

[iPeekYou]

Yes, I've realized there are many threads of this nature already, however I have a case that I have not found exactly like mine.

I bought some new RAM sticks ( a kit of 2x 4 GB DDR3) to add to my existing 8 GB kit. The PC booted up and I hit UEFI just fine, set the memory speed to match (they were 1333 in slots 2 and 4, and the new ones were 1600 in slots 1 and 3 so I tried to downclock the new ones to 1333).

Saved settings, and rebooted from UEFI. The PC started BSODing twice, and I figured I might have to tinker with the RAM config so I let it restart.
Well, if it would. It didn't power on at all, let alone boot after the BSOD auto restart. No fans, no LEDs, no activity at all when I hit the case switch.

Took apart the PC, and stripped everything down to just CPU, HSF, and the PSU plugged in. Still nothing.

Checked and rechecked the standoff screws, and for any loose screws/wires that might short things inside the case.

Tried to jump start from the MB itself, nothing.

Pulled the 24ATX plug, and tried the paperclip test to a case fan, it spins the fan.

Plugged in the 24ATX back in, and used the paperclip that way. This time all the case fans and the CPU fan spin. Plugged in HDD and touched it, I can feel it spin, if a bit weak. None of the other functionalities including front panel switch, power LED, or anything works still. Had to turn off the PSU to shut it down.
.....and that's the extent of what I did.

I guessed perhaps the PSU is weak, and only can just power up the fans and send a little bit over to SATA (hence the HDD weak spin). I fear the MB might be toast....but the CPU fan and another fan plugged (both plugged in to the MB) works. So I'm not entirely sure.

Could've been the RAM causing all these? The RAM sticks work in another system that I tested after.

Unfortunately, I have no spare PSU or same socket MB lying around to truly swap in and test at the moment. Any guesses or help diagnosing the MB? While I scrounge around local shops for spare PSU to breadboard and test. Thanks in advance.

i5 3470 with stock HSF
RX 580
MSI B75MA-P45
2x 4GB Team Elite DDR3 1333Mhz
(new but I left it out atm) 2x 4GB Hynix 4GB DDR3 1600MHz
Corsair VS650

System is 7-8 years old at this point, except the new RAM and the GPU.

 

[Lutfij]

Yeah, if the PSU is 8 years old meaning that it's the yellow/orange labelled VS series PSU, you're in need of replacing the unit with a brand new reliably built unit. The VS mind you isn't a good unit in spite of being in Corsair's lineup. I'd suggest a TX unit with 650W to spare for the entire system.

On another note, have you tried removing the CMOS battery from the motherbaord while the system is powered down?

Paperclip tests don't indicate how much power the PSU can output, but it does show that the PSU isn't dead either but it's not a way to verify that the PSU has XYZ watts still left to pump out to the entire system.

 

[iPeekYou]

Yeah, if the PSU is 8 years old meaning that it's the yellow/orange labelled VS series PSU, you're in need of replacing the unit with a brand new reliably built unit. The VS mind you isn't a good unit in spite of being in Corsair's lineup. I'd suggest a TX unit with 650W to spare for the entire system.

On another note, have you tried removing the CMOS battery from the motherbaord while the system is powered down?

Paperclip tests don't indicate how much power the PSU can output, but it does show that the PSU isn't dead either but it's not a way to verify that the PSU has XYZ watts still left to pump out to the entire system.

Yeah, that's what I figured. I'm currently looking at decent Superflowers and Antecs locally to replace the Corsair if it comes to that. Perhaps the added load from the new sticks, coupled with the GPU finally kicked the bucket for my PSU (previously had GTX 660).

I thought heck even decent PSUs have what, 3 to 5 yrs warranty and mine is a budget one that ran for 8 years and it had a good run already.

And yeah, I pulled out the CMOS battery, left it for 15 minutes off (also pushed the case switch for 30 seconds and jumped the pins for 30 secs as well) with no results. Pulled everything including the battery overnight and tested it this afternoon with nothing happening as well.

Any ideas to further test the MB and/or PSU? I'm waiting for tomorrow so I can get my hands on another spare PSU (crap 450w unit) to plug in a bare MB+CPU+HSF combo to confirm, and I'd like to narrow down my problems as much as possible in the meantime.

Edit: My guess is the PSU isn't supplying power to the 5V rail for the front panel switches and MB logic, and very weak on 12v only enough for the fans (including CPU fan?) and partially for the HDD. Plugged in PCIe power and the GPU fans don't even spin

 

[iPeekYou]

Update: plugged in a spare PSU from work PC, no go. Exact same symptoms as I already had.

That PSU was a crap sub 300w one that has no switch even...but with only MB+CPU hooked up surely it's enough to at least POST.

Well....am I looking at a dead MB now? Can't think of any more things to test short of pulling the CPU out to a donor MB to rule out dead MB/CPU.

 

[iPeekYou]

Turns out the MB was toast. PSU tested normal at all voltages...and replacing the MB solves the issue completely.
Never thought a bad RAM combo can kill a motherboard but there it is apparently