Question PC turns on then off before bios (nothing on screen)

pizzalover

Honorable
Mar 29, 2014
8
0
10,510
0
Hello community!

Having a bit of an issue with a new PC build. Two days ago I finished putting the computer together, powered it on, everything worked perfectly. Got windows installed, did all the updates, played a bunch of games. Temperatures were perfectly reasonable, overall I thought it was a great success. The computer was left off for about 1 day, nothing was touched or changed, and then last night I tried to power it on and...
  1. The PC powers on (as in the power light on the case and the fans lights all turn on)
  2. There is nothing that comes on the screen (no motherboard logo, nothing)
  3. There are no beeps (I'm not sure if this mobo even has a speaker)
  4. Then after a few seconds, it powers off by itself, then powers back on, and the cycle continues
Immediately I thought it was a faulty power supply (Sharkoon silent storm cool zero 750w). It has been replaced with a brand new Corsair RM850x this morning, but the exact same issue continues.

Have tried:
  • Replacing the power supply
  • Reseating all power connections
  • Removed the GPU and plugged the monitor directly into the mobo hdmi
  • Removed the secondary hard drive
  • Removed the power, the battery on the mobo, and held the power button for 1 minute
  • Reset cmos using a jumper
I am about to pull the whole thing apart and test it on the bench, but hoping you might have some advice before I get to that. I hope it isn't something serious!

Corsair RM850x
ASRock z490 pro4
i7 10700k
Corsair H100i RGB Platinum SE
G.Skill TridentZ RGB 3600 (32gb)
WD Blue m.2 1TB
Gigabyte 2080 super
Fractal design meshify c case
 
Last edited:

Lutfij

Titan
Moderator
Breadboarding would've been the first thing I'd have done to the system after the system failed to boot. Mind stating what you changed the PSU to to rule out that the PSU(s) are not faulty...? Perhaps try and inspect the CPU socket for any bent or broken pins.
 
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pizzalover

Honorable
Mar 29, 2014
8
0
10,510
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The original PSU was a Sharkoon cool zero 750w. If you haven't heard of this brand, neither had I, but I was convinced by the customer service rep to get this after the EVGA psu I originally wanted went out of stock. I'm in Germany building this for my gf (I'm from Canada). Now the PSU is the Corsair RM850x (a reputable brand I trust, unlike Sharkoon).
 

Lutfij

Titan
Moderator
I've heard of Sharkoon from 2009 and back then they only made fans that had dimples on their blades like a golf ball which was all the rave back then, before Noctua and Be Quiet! became market dominators in silent fans.

Right, please post a followup when you're breadboarded and with only the bare minimum parts on the board, after the CPU socket is shown to have no bent or broken pins. You might want to also inspect how tight the cooler is on, maybe do a couple of rotations anti clockwise to loosen it a little but still have them fasten the cooler on. Leave all RGB cables out, bare minimum.

Also as for the CMOS battery, remove the battery for at least 15 minutes before plonking it back in.
 
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Joseph57

Honorable
Mar 27, 2014
50
10
10,545
2
A bad memory module could cause an issue like that too.
remove all the memory except for one module and check a boot up with each memory stick one at a time. First try the proper slot and then try the other memory slots.
If you have another pc that is compatible with these memory sticks, try using them in that to see if there is any issues
 
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Ziadul87

Prominent
Sep 7, 2019
490
48
740
21
Hello community!

Having a bit of an issue with a new PC build. Two days ago I finished putting the computer together, powered it on, everything worked perfectly. Got windows installed, did all the updates, played a bunch of games. Temperatures were perfectly reasonable, overall I thought it was a great success. The computer was left off for about 1 day, nothing was touched or changed, and then last night I tried to power it on and...
  1. The PC powers on (as in the power light on the case and the fans lights all turn on)
  2. There is nothing that comes on the screen (no motherboard logo, nothing)
  3. There are no beeps (I'm not sure if this mobo even has a speaker)
  4. Then after a few seconds, it powers off by itself, then powers back on, and the cycle continues
Immediately I thought it was a faulty power supply (Sharkoon silent storm cool zero 750w). It has been replaced with a brand new Corsair RM850x this morning, but the exact same issue continues.

Have tried:
  • Replacing the power supply
  • Reseating all power connections
  • Removed the GPU and plugged the monitor directly into the mobo hdmi
  • Removed the secondary hard drive
  • Removed the power, the battery on the mobo, and held the power button for 1 minute
  • Reset cmos using a jumper
I am about to pull the whole thing apart and test it on the bench, but hoping you might have some advice before I get to that. I hope it isn't something serious!

Corsair RM850x
ASRock z490 pro4
i7 10700k
Corsair H100i RGB Platinum SE
G.Skill TridentZ RGB 3600 (32gb)
WD Blue m.2 1TB
Gigabyte 2080 super
Fractal design meshify c case
Happened to me because my RAM slots were too tight and I didn't apply enough pressure. The module was in, the hook successfully caught it, but it still required more pressure(quite a lot, I was afraid I might bend the MoBo)
 
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pizzalover

Honorable
Mar 29, 2014
8
0
10,510
0
Thank you very much for the feedback. My plan is:
  1. Disconnect everything from the mobo except the bare necessities
  2. 15 minute CMOS battery reset
  3. Reseat RAM / cycle each stick through each slot
  4. Take everything out of the case and try again
  5. Look at cpu / pins / cooling / heatsink compound, etc... but I HIGHLY doubt this is the issue because like I said, everything was fine (temps were great even at high load) when I first turned it on and then stopped working a day later.
 

pizzalover

Honorable
Mar 29, 2014
8
0
10,510
0
OK I have taken everything out of the case and the only thing connected is:
  • motherboard power
  • 8 pin cpu power (have tried with 8 pin and 8+4 pin)
  • power switch from case
  • cpu
  • CPU cooler + sata power for pump + 2 radiator fans connected to the cooler. Cooler connector to CPU_FAN1 as directed in the Corsair manual
  • ram (have tried one stick in each slot, then the other stick in each slot)
  • taken cmos battery out for 15 mins and jumpered the cmos reset
Same issue... Powers on for 10 seconds with nothing on the screen (no logo or bios options or anything), then powers off for 5 seconds, then powers on again, repeat.

Next step is take off the cooler, check the compound and CPU pins?
 

pizzalover

Honorable
Mar 29, 2014
8
0
10,510
0
I've heard of Sharkoon from 2009 and back then they only made fans that had dimples on their blades like a golf ball which was all the rave back then, before Noctua and Be Quiet! became market dominators in silent fans.

Right, please post a followup when you're breadboarded and with only the bare minimum parts on the board, after the CPU socket is shown to have no bent or broken pins. You might want to also inspect how tight the cooler is on, maybe do a couple of rotations anti clockwise to loosen it a little but still have them fasten the cooler on. Leave all RGB cables out, bare minimum.

Also as for the CMOS battery, remove the battery for at least 15 minutes before plonking it back in.
We have everything breadboarded now and have:
  • Removed cpu cooler and cpu
  • CPU looks perfect and so do all the pins on the board (none bent or broken)
  • Cleaned cpu and cooler (99.9% isopropyl + microfibre cloth)
  • Reinstalled CPU, applied pea size of MX-4 and reinstalled the cooler
Exact same issue:
  1. Computer powers on (lights + fans spinning)
  2. No image on monitor, no beeps (don't think the mobo has a speaker)
  3. Stays on for about 10 seconds, shuts off by itself, stays off for 5 seconds, then turns on again
  4. Cycles like this continuously
Only things installed:
  • motherboard power
  • 8 pin + 4pin cpu power (have tried with 8 pin and 8+4 pin)
  • power switch from case
  • cpu
  • CPU cooler + sata power for pump + 2 radiator fans connected to the cooler. Cooler connector to CPU_FAN1 as directed in the Corsair manual
  • ram (have tried one stick in each slot, then the other stick in each slot). currently 2x16gb in A2 and B2 slots (as directed in the asrock manual)
Time to replace RAM, CPU and mobo? Which would you consider doing first?
 

Ziadul87

Prominent
Sep 7, 2019
490
48
740
21
We have everything breadboarded now and have:
  • Removed cpu cooler and cpu
  • CPU looks perfect and so do all the pins on the board (none bent or broken)
  • Cleaned cpu and cooler (99.9% isopropyl + microfibre cloth)
  • Reinstalled CPU, applied pea size of MX-4 and reinstalled the cooler
Exact same issue:
  1. Computer powers on (lights + fans spinning)
  2. No image on monitor, no beeps (don't think the mobo has a speaker)
  3. Stays on for about 10 seconds, shuts off by itself, stays off for 5 seconds, then turns on again
  4. Cycles like this continuously
Only things installed:
  • motherboard power
  • 8 pin + 4pin cpu power (have tried with 8 pin and 8+4 pin)
  • power switch from case
  • cpu
  • CPU cooler + sata power for pump + 2 radiator fans connected to the cooler. Cooler connector to CPU_FAN1 as directed in the Corsair manual
  • ram (have tried one stick in each slot, then the other stick in each slot). currently 2x16gb in A2 and B2 slots (as directed in the asrock manual)
Time to replace RAM, CPU and mobo? Which would you consider doing first?
Likely the Mobo. Could you try using the Rams and CPU on a friend's PC or vice versa? That would've narrowed it down.
 
Last edited:

pizzalover

Honorable
Mar 29, 2014
8
0
10,510
0
Likely the Mobo. Could you try using the Rams and CPU on a friend's PC or vice versa? That would've narrowed it down.
Thanks, unfortunately we don't have anyone with a z490 / 1200 board, so it looks like we'll be bringing it in to a repair shop for diagnostics. Sucks to get defective hardware, especially when it works perfectly for a couple days and then dies!

Thanks for your help :)
 

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