Member Avatar for anlogue

Simply is it possible for the PC (motherboard) to blow PSU'S I.E.from a shorting motherboard or other device on the mobo

Have been fixing PC'S for years but this scared me and my pocket,

The PC had a blown smokey PSU, I replaced with a second hand known working unit.... this blew.....then a new unit....... this blew
im not putting anything else in there till i talk to someone...

This PC has been troublesome for a month, ranging from a failed CPU Fan, a modem that stopped the PC Booting (no posts) and software glithches. Its tired out.


I have 2 more PSU units i have tested them in my test PC and they are working:p

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Multiple PSUs failing in one build is a clear sign of a persistent hard fault that will keep damaging replacements. Given ’s report and ’s chassis-contact anecdote, treat the motherboard assembly as suspect and stop swapping ordinary PSUs in until the fault is isolated. ’s encouragement to hunt for shorts is the right direction; the following is a practical, safer workflow to find the fault and protect any next power unit.

First, protect the next PSU: use a bench power supply with current limiting or put an incandescent 12V lamp in series with the 12V feed as a simple current limiter. That stops a hard short from drawing destructive current and gives a visible/heating indication of heavy draw. Work on the bench with the board removed from the case and sitting on cardboard or an antistatic mat. Only connect the minimum (CPU + cooler, one RAM stick, CPU 4/8‑pin and 24‑pin power) and try to power up under current-limited conditions.

If the limiter shows heavy draw immediately, localize the short: visually inspect under magnification for solder bridges or crushed components around the CPU VRM/connector areas; use a DMM diode/continuity check on MOSFETs, diodes and shunt resistors (unpowered board). A thermal camera or brief power under current limit will quickly reveal a component heating up. If the system only trips when a card or drive is added, test that peripheral in a known-good machine.

Protect client data before doing destructive testing: remove and image the drive(s) first. If the board is badly damaged or the fault is deep (blown VRM MOSFETs, cracked multilayer PCB), replacing the motherboard and case and migrating the drives is often the fastest professional fix. If continuing diagnostics, always use current-limited power, document what blew and when, and consider professional repair if the fault can’t be isolated safely.

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Member Avatar for DMR

Simply is it possible for the PC (motherboard) to blow PSU'S I.E.from a shorting motherboard or other device on the mobo

Yes- definitely possible, especially if it's a very hard short straight to chassis ground. We've had a few members who had similar experiences, and at least one of them found that a screw securing their motherboard had made contact with a 12V motherboard trace at one end, and was touching the bare metal chassis at the other end. A badly-shorted component like a capacitor could have the same effect.

If you have a multimeter, you might be able to narrow down the location of the fault by testing for lack of resistance between the different circuit traces/power rails and chassis ground. You should also inspect (look and smell) the motherboard and all other components for signs of physical/thermal damage.

Member Avatar for anlogue

this pc belongs to a client, i think my course of action will be to look for the exact same motherboard, a nice new case and load in the cards one by one. I may stick in a new cpu as well as there not short of cash. Its a compromise but you have to look professional and they have vital docs and proges in the setup.
trouble is i cant find a Asus A7A266 MOBO on ebay

Thx for your help

Member Avatar for jbennet

this happened on my dads box as the mobo wasnt on the foam so it was shorting by touching the metal sides of the case

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