Hi, I'm Daniel, and I'm new to the world of repairing motherboards.

I would like to create a table, or more likely a guideline about the voltage rails and their possible resistance rail.

I know that the motherboard design has a very big depend on the rail's resistance, but I would like to know what is the smallest value for a rail that can be acceptable. For example, I heard that some new gaming motherboards can have 0,5 Ohm resistance on the GPU rail, but on an older type, it could be a sign of a shorted GPU rail.

So, I generated a table with AI so I can...

Hello everyone,

I'm trying to repair my old Acer Nitro 5 (AN517-54-55T5). I've already bought a new laptop, so this is more of a learning project. For the experience, with no high expectations of success.

Well, my decice specs are the following:

Model: Acer Nitro 5 AN517-54-55T5
CPU: Intel Core i5-11400H
GPU: NVIDIA GeForce GTX 1650
Motherboard: GH51G LA-L181P Rev:1c

The symptom:
When pressing the power button, the power LED lights up for about 5 seconds and then turns off. Initially, the issue was intermittent: sometimes...

Hello Everyone,

Long story short, I got this unit for very cheap.
I've started to experiment with it's BIOS, as I did before successfully with an M900. However my very bad quality SOIC clip broken while dumping of the biosof and it must have damaged something on the panel, because it does not turn on, and does exactly nothing when powered. The maximum voltage that could have affected something is the 3.3 or 5v from the IC clip, because the unit was not powered while the bios dumping was in progress.

I've performed some measurements:
- 20V rail perfectly...

Hi,

A colleague gave me an apparently ill CORSAIR CX600.
He told me that he heard a banging noise, and smelt the magic smoke.
After tearing down the PSU, no burnt component, everything seems OK, but the PSU often refuses to stay ON. When shorting PS_ON to GND, the fan spins a bit a finally stops. No output voltages.

I tried to treat some apparently bad solder joins and finally it seems to work OK... on the 12V and 5V rails!
It's another story on the 3.3V rail...

I have some devices to test deeply PSUs (scope, AC source, electronic load)...

Hi guys,

I’m working on an Asus Q409ZA motherboard (NB5936_MB_V3) in my lab that does not boot. I already reprogrammed the BIOS chip but the behavior did not change.

Powering the board via USB-C, I measure about 20.23 V and 0.2 A at startup, and these values remain completely stable with no current or voltage oscillation. Using a thermal camera, I see the CPU heating up to around 60–70 °C, and next to the CPU there is a QFN chip marked “NFDF” (PU1301) that heats up to about 40 °C and is supplied by the V1P8A rail. The V1P8A rail is shorted to ground and does...