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Old 04-24-2018, 10:36 AM   #1
enseitankado
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Join Date: Apr 2018
City & State: Samsun
My Country: Turkey
I'm a: Knowledge Seeker
Posts: 3
Default Vcore leak/spike at MSI P4M900M2 motherboard

I'm working on faulty MSI P4M900M2 mainboard.
First, I accept that it is outdated board, the repairs forced me so much that it turned into a personal challenge.
Because I am trying to record an educational video for my students. I think I spent almost 15 hours working. Of course I also agree that I am not an expert on motherboard repairing.

At first, there was not a Vcore and was short-circuit on power input of CPU. I checked alot of components and inspect short-curcit at front-end of CPU PWM controller and power mosfet at phase of Vcore. Also open-circuit 2.2Ohm smd. I changed all of them. Now, mainboard can start but Vcore mosfets and the CPU itself overheating in 30secs and enters thermal protection.

When I was look Vcore's wave shape detect a spike/leak square waveform. I attached it the post.

After this tested each of the Vcore phase groups (3xMosfet) separately (via desoldering each of groups), but result not changed.

I could not detect a fault component around the CPU pwm controller and vcore mosfets. ie short-circuit or open-circuit elements.

I need your advice and experience in this regard. Where else should I focus. Thanks already for your help.
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