Question PC won't post, keeps rebooting despite having replaced all major components

[Yggdrasilbury]

I think I’ve tried everything to get my trusty computer back up and running, and could really use some help from people more knowledgeable than myself.

My computer suddenly wouldn’t post with no previous warning, so I set about to fix it, while getting some new components in at the same time.

Nothing I’ve tried works - the computer starts, the MB, GPU and LED lights come on, the fans spin, but only for around 40 seconds - then it reboots, and the same thing happens.

I’ve replaced the motherboard (first on the suspect list), replaced the PSU (upgraded to a 750W from a 650W), I’ve replaced the CPU (upgraded my Ryzen 7 1800X to a 3700X), I’ve replaced my RTX 3700 with an RTX Titan), I’ve shuffled around the RAM, I reseated all connectors, I’ve cleared the CMOS (both shortening the PINs and removing the battery) - no change whatsoever.

After weeks of struggling with this, I’m all out of ideas, and would be extremely grateful for any help from you guys.

Maybe I’m just missing something stupid, after having put everything together again with the new parts (CPU and GPU - I went back to my original motherboard after replacing it made no change).

This is my setup:

Motherboard: ASRock X370 Killer SLI (tried switching out with a ASRock X570 Taichi Premium, switched back after no change - exact same behavior)
PSU: Corsair CX750
CPU: Ryzen 7 3700X
GPU: Nvidia RTX Titan
RAM: 4 x 16GB DDR-4 (2 x Ripjaws GSkill + 2 x XPG AData)
CPU Cooler: CyberPower PC-branded liquid cooler (looks simila to a Corsair H60)
Case: Phantek5

 

[triplex1]

I think I’ve tried everything to get my trusty computer back up and running, and could really use some help from people more knowledgeable than myself.

My computer suddenly wouldn’t post with no previous warning, so I set about to fix it, while getting some new components in at the same time.

Nothing I’ve tried works - the computer starts, the MB, GPU and LED lights come on, the fans spin, but only for around 40 seconds - then it reboots, and the same thing happens.

I’ve replaced the motherboard (first on the suspect list), replaced the PSU (upgraded to a 750W from a 650W), I’ve replaced the CPU (upgraded my Ryzen 7 1800X to a 3700X), I’ve replaced my RTX 3700 with an RTX Titan), I’ve shuffled around the RAM, I reseated all connectors, I’ve cleared the CMOS (both shortening the PINs and removing the battery) - no change whatsoever.

After weeks of struggling with this, I’m all out of ideas, and would be extremely grateful for any help from you guys.

Maybe I’m just missing something stupid, after having put everything together again with the new parts (CPU and GPU - I went back to my original motherboard after replacing it made no change).

This is my setup:

Motherboard: ASRock X370 Killer SLI (tried switching out with a ASRock X570 Taichi Premium, switched back after no change - exact same behavior)
PSU: Corsair CX750
CPU: Ryzen 7 3700X
GPU: Nvidia RTX Titan
RAM: 4 x 16GB DDR-4 (2 x Ripjaws GSkill + 2 x XPG AData)
CPU Cooler: CyberPower PC-branded liquid cooler (looks simila to a Corsair H60)
Case: Phantek5

Check your processor if it has paste or any bent pin.

 

[JohnBonhamsGhost]

PSU: Corsair CX750

the CX series has pretty much always been problem units with very high rates of failure and issues delivering steady power.

unless this is some new rebranding of that series from Corsair with much higher quality materials and design, it is likely not able to consistently provide reliable power.

 

[Yggdrasilbury]

the CX series has pretty much always been problem units with very high rates of failure and issues delivering steady power.

unless this is some new rebranding of that series from Corsair with much higher quality materials and design, it is likely not able to consistently provide reliable power.

Oh no... I thought it would be a good upgrade fom my 650, which had nve given me any problems.

I haven't measured the output of the 750, but perhaps I should.

I'm thinking I might be overlooking something stupid, or have connected things incorrectly.

 

[Yggdrasilbury]

Check your processor if it has paste or any bent pin.

Thank you. I don't have any paste on it yet as it's brand new, I didn't think I'd need it just to test whether the system would post.

I'll recheck it for bent pins - I did take a close look at the CPU socket and shot a photo of it so I could zoom in, but I didn't see any bent pins there.

Could it be the cooler somehow? I did get a stock cooler with the new CPU, and replacing the liquid cooler with that is one of the few things I haven't tried (I was wary of the noise it would make).

 

[JohnBonhamsGhost]

haven't measured the output of the 750, but perhaps I should

getting a measured output doesn't give you the overall build quality or the problems that may occur with strain at different peak usages,
just a basic output level.

 

[HydroXzX]

Make sure your MB isint shorting out on the back of the case somewhere and proper standoffs are installed and they arent touching a circuit or something

 

[KingLoki]

As a last resort, you may need to remove the motherboard, disconnect all external devices, as well as any drives. Sit the board on cardboard and just leave the ram and gpu and power connected. Power the system on and see if it posts and sits with no reboots.