Member Avatar for Ritesh_4

Hello,

Am currently facing a problem with my home PC, whereby upon switching on, all the lights switch on normally (HDD, DVD-drives, PSU), then just seconds later, it switches off by itself, and again some seconds later, starts to switch on by itself, but again goes off (in a loop). No beep sound whatsoever.

Any one can help troubleshoot this issue?

Thanks.

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  • Latest Post Latest Post by Akshay_9

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Good to see got the machine stable. That said, the on/off loop you described is a common intermittent-fault pattern; it can come from several places beyond the isolation steps already suggested by and the thermal observation from . The short checklist below collects practical checks and safe next steps for anyone who hits the same symptom later.

  • Front-panel harness and connectors: remove the case front-panel wiring (power, reset, USB/audio) from the motherboard and inspect for frayed wires or corrosion. A sticky or shorting power switch will cause cycling.
  • CPU/EPS and 24-pin ATX power: confirm the 4/8-pin CPU power and main 24-pin are fully latched, pins straight, and free of burn marks; intermittent contact here can kill the boot instantly.
  • Visual board inspection: look for bulging/leaking capacitors, scorch marks or swollen components around the CPU/VRM area—these point to motherboard failure rather than a drive or OS issue.
  • Drive spin‑up/inrush: note whether the cycle aligns with drive spin-up; a failing drive or enclosure can create an inrush that trips a marginal PSU.
  • POST feedback and CMOS: attach a small system speaker or use onboard debug LEDs to capture POST codes. Clear the CMOS if POST data looks corrupted; only flash BIOS after the system is reliably stable.
  • Definitive swaps: a PSU can appear alive but still fail under load. If the fault returns, test with a known-good PSU or known-good motherboard to isolate the failing subsystem.

Work with mains power disconnected while rearranging cables, use ESD precautions, and avoid live-probing unless experienced.

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Member Avatar for rproffitt

I can share what we do in the shop with such a PC. Ready? We downsize it. Any component that isn't required to get a BIOS screen is removed. If that doesn't bring it back we remove the case because a lot of homebuilt PCs have extra mounting posts and create issues.

So if you downsize it to just motherboard, CPU+HSF, one stick of RAM and PSU without a case and it still doesn't stay up, it's one of those 4 parts.

commented: worked with bare minimums +7
Member Avatar for Ritesh_4

rproffitt, did as you suggested, but first went for the "paper-clip" test with the psu. its fan started to run as soon as I switched the power on. Decided to connect only motherboard and psu, and switched on fine. Plugged all my internal hardware again, and the PC started properly.
So am still unsure on what caused this issue in the first place... Will keep a watch for a few more days...

Member Avatar for rproffitt

@R, that usually points to assembly errors. Most common find is an extra mounting post in the case randomly touching the back side of the motherboard. Drives the owner nuts as it works then not and takes it in and it works.

I've lost count how many times we see that issue.

Member Avatar for rubberman

I've had similar problems when either the CPU or RAM would overheat. As a Linux user, I had access to the sensors tool and could monitor the temperature of these parts. I found that the RAM was overheating, but because I was only using 1/2 of the available slots, I staggered the spacing and the problem went away. Now, it runs nice and cool! At 10+ years old, it is still a kick-### server! Dual quad-core Intel chips and 8GB of RAM. Also, it, being custom built, has a 1000 watt PS. Never go cheap on the power supply!

Edited by rubberman
Member Avatar for Ritesh_4

Problem seems to have been solved, as PC is running properly

Member Avatar for Subraa_1

Good for you Ritesh! - it should have been a RAM issue - I would say from my experience!

Member Avatar for pdsubbu

What was the issue @ Ritesh?

Your experience could help someone else

Member Avatar for Akshay_9

I think applying heatsink to the cpu fan will solve the problem

commented: Sounds messy to me. Won't it go flying off at speed? +12
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