Question Corsair RM750 dead or not?

Jul 24, 2020
10
2
15
0
I've just finished my pc build yesterday and was plagued by the DRAM LED light on the mobo (I'll save for another thread). The system started yesterday perfectly and was running for a total of at least 15 minutes. Today, as I was fixing the RAM problem (shifting them down a slot), the system wouldn't turn on. I tried resetting the bios by taking out the battery and powering off for 30 seconds. It worked the first time but then it didn't. After that the system would not turn on...after 10-20 minutes, the computer would magically turn on. Now, in the rare event that the computer turns on, it would turn off after a couple of minutes. It mostly stays off. What's the problem?

Notes:

  • Components below
  • I tried the paperclip test on the PSU and it failed (no power)
  • Resetting the BIOS failed
  • I used a wattage calculator and it came out to 600w
  • Is 750 w enough?
 

Juular

Prominent
Mar 14, 2020
554
115
590
19
If you're sure that the CPU isn't overheating then it's pretty much PSU problem - yes. Check CPU temperatures, if they're okay then contact Corsair.
 

Vic 40

Polypheme
Ambassador
  • I tried the paperclip test on the PSU and it failed (no power)
Tried that with an additional fan attached? If you have a molex powered fan that should work.

Tried breadboarding? Take the motherboard out of the case, put it on the box it came in, only use cpu+gpu+1 stick of ram (second slot from the cpu out), see if you can get into the bios and if that is stable.

Also can try "usb bios flashback" and flash latest bios when breadboarded, maybe that will help if you don't have it.
 
Last edited:
Jul 24, 2020
10
2
15
0
I ended up swapping out the PSU for another one and it still won't power on. This time it doesn't power on even once. I tried shorting the power switch, swapped the power cable and tried a different outlet. Any ideas?
 

egda23

Upstanding
Jun 14, 2020
428
76
290
15
I ended up swapping out the PSU for another one and it still won't power on. This time it doesn't power on even once. I tried shorting the power switch, swapped the power cable and tried a different outlet. Any ideas?
Did you carefully put the risers under the motherboard when you build the system ? (if not you will have a short with exactly your symptoms)
Tried booting without the GPU (obviouslyyou won't have any image on screen, but you will see the system booting)? Take the GPU completely out (not just disconnecting).
If no difference, test with one RAM stick at a time, always put it in DIMMA2 (as per manual).
After that, take out SSD and disconnect the optical drive.
If nothing helps, do as said by Vic 40 : try breadboarding

And the one million $ question: are you positive that the 24 pin power connector, 8 pin power connector, and CPU_FAN connector are completely, well..., connected ...
 
Last edited:

egda23

Upstanding
Jun 14, 2020
428
76
290
15
And another thing, your RAM is not referenced on the MoBo's QVL. And no 32 GB sticks with such a high speed (3600 MHz) is on this list. Could be a clue.
Have you another DDR4 stick to put in the PC without the present RAM ?
 

Mr.Spock

Prominent
Dec 8, 2019
667
74
740
76
shifting the RAM may have caused a card to come loose - reseat the GPU and check the ATX connections. you may need to clear CMOS too. doubtful it's the PSU being too weak since you wouldn't be under load at startup - probably a short somewhere.
 
Jul 24, 2020
10
2
15
0
Did you carefully put the risers under the motherboard when you build the system ? (if not you will have a short with exactly your symptoms)
Tried booting without the GPU (obviouslyyou won't have any image on screen, but you will see the system booting)? Take the GPU completely out (not just disconnecting).
If no difference, test with one RAM stick at a time, always put it in DIMMA2 (as per manual).
After that, take out SSD and disconnect the optical drive.
If nothing helps, do as said by Vic 40 : try breadboarding

And the one million $ question: are you positive that the 24 pin power connector, 8 pin power connector, and CPU_FAN connector are completely, well..., connected ...
Yes I'm positive, i bought a PSU tester and indeed the PSU is working and plugged the 24pin back into the MOBO. The MOBO is definitely not responding (no test lights).
 
Jul 24, 2020
10
2
15
0
And another thing, your RAM is not referenced on the MoBo's QVL. And no 32 GB sticks with such a high speed (3600 MHz) is on this list. Could be a clue.
Have you another DDR4 stick to put in the PC without the present RAM ?
Oh i have the 3200 (which is on the QVL) not the 3600. The system has worked a couple of times (literally only a couple of times) with the ram and got into BIOS (as you can see in OP's) but now the MOBO is practically dead.
 
Jul 24, 2020
10
2
15
0
Did you carefully put the risers under the motherboard when you build the system ? (if not you will have a short with exactly your symptoms)
Tried booting without the GPU (obviouslyyou won't have any image on screen, but you will see the system booting)? Take the GPU completely out (not just disconnecting).
If no difference, test with one RAM stick at a time, always put it in DIMMA2 (as per manual).
After that, take out SSD and disconnect the optical drive.
If nothing helps, do as said by Vic 40 : try breadboarding

And the one million $ question: are you positive that the 24 pin power connector, 8 pin power connector, and CPU_FAN connector are completely, well..., connected ...
I don't have the skills or much time to do breadboarding. I called MSI but their CS was garbage - they didn't do any diagnosis and want me to pay return shipping. What do you think?
 

Vic 40

Polypheme
Ambassador
I don't have the skills or much time to do breadboarding. I called MSI but their CS was garbage - they didn't do any diagnosis and want me to pay return shipping. What do you think?
You don't have time to breadboard, but have time to test other stuff? And rma usually means you pay fo return shipping. Might be good to try.

You tried the usb bios flashback i suggested?
 
Jul 24, 2020
10
2
15
0
You don't have time to breadboard, but have time to test other stuff? And rma usually means you pay fo return shipping. Might be good to try.

You tried the usb bios flashback i suggested?
If this is not a problem that I caused, why am I forced to pay return shipping? Since this is a QC issue with MSI, shouldn't they cover the bill? I haven't even used the computer yet - windows isn't even installed...When we thought the problem was with the PSU, corsair happily covered return and delivery shipping costs. That's how it should be done.

Yes i tried the USB BIOS flash back - since there wasn't any power going to the MB, nothing happened.
 
Jul 24, 2020
10
2
15
0
My friend fixed it said someone on a forum suggested connecting one 4pin cable to the 8 pin cpu power and another 4pin cable to the other 4pin cpu power. As soon as he did that it started and was able to install windows
 
Reactions: Vic 40

ASK THE COMMUNITY

TRENDING THREADS