Member Avatar for dlawson1986

I recently replaced my motherboard, cpu, and ram in my desktop and it works fine. I had a spare power supply (about 1 year and 6 months old, NEVER used, it came with my case) so I decided to take my old hardware and build spare pc. I got everything hooked up and when it came time to power it up nothing happened. I noticed that everytime I plug in my power cable, I can hear a very faint "whistle" noise coming from the pc. I cant pinpoint exactly where its coming from because it is so faint. At that point I plugged in a known working power supply and it does the exact same thing. I've done everything I can think of and still now luck. Anyone have any ideas?

Thanks in advance

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  • Latest Post Latest Post by jbennet

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A faint high-pitched whistle when you plug the PC in usually points at either a PSU under stress or a board short. Since ended up with a short (as suggested and tried to help locate by ear), run these follow-ups to confirm nothing else was damaged and to avoid repeats.

Visual and mechanical checks: power down and unplug, then remove the board and look closely for missing/misaligned standoffs, stray screws or metal fragments, scratched PCB traces, burnt marks, or bulging/leaking capacitors. Make sure the I/O shield is seated correctly and not touching traces. If you find scorch marks or smell burned components, do not power it again.

PSU and electrical checks: a paperclip test only spins the PSU fan and does not verify regulated rails. Use a PSU tester or a multimeter to check the +12V, +5V and +3.3V outputs under load, and inspect the 24-pin and CPU 4/8-pin connectors for discoloration or melted plastic. Be careful probing live connectors; if you are not comfortable, let a shop test the unit. Background: PSU operation and short-circuit effects are covered here: Power supply unit (computer) and Short circuit.

Boot and validation: bench the board on a nonconductive surface with CPU, cooler, and one RAM stick; attach a speaker for POST beeps. If it POSTS, run Memtest86 for RAM and a CPU/memory stress test to verify stability: Memtest86. If it will not POST on a minimal setup, swap components into a known-good system or have the motherboard/PSU checked for blown MOSFETs/fuses or damaged traces.

Prevention: always fit the correct standoffs and fasteners before mounting, keep the case clear of metal debris, use ESD precautions, and bench-test new builds before final assembly.

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Member Avatar for jbennet

is it shorting?

make sure the standoffs are in

Member Avatar for dlawson1986

is it shorting?

make sure the standoffs are in

I did miss one, and I had to reseat the motherboard to get them all in but its still doing the same thing.

Member Avatar for caperjack

open computer case .lay it flat on its side ,turn it on, hover you head all around listing with you best ear into the open case ,and you should be able to pinpoint the whistle

Member Avatar for dlawson1986

I got it running. As jbennet said, it was shorting.
Thanks

Member Avatar for jbennet

you might of damaged it by shorting it, run diagnostics to check

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