no liquid damage. I got it from a friend that says the unit stop to working. Now when i plug it i can see only led to blinking. i will che the voltage you suggested me and reply to you soon.
Can you clarify? There is still a FB connection resistor @ R7820. Carefully remove it. Do not power up without these components. Great that you are comfortable with this process as the parts are incredibly small. There is also a cluster of pins on U7800 that directly bond to this rail (R12, T12, etc.) - so U7800 is still a suspect.
Then confirm which side of this rail is shorted? Is it the producer (U7800) or consumer side. In your post, do share the pin # of the removed coil(s) that show the 44 ohms to ground.
One tool that would help here and we are considering it to source soon is a low ESR capacitance meter that can measure in milli-ohms. With such a tool, it should be possible to test each cap or whatever on the board to confirm if it is shorted or not. There is a sea of parts onboard to investigate.
Well,I removed R7820 too and still I have low resistance consumer side. There are a lot of capacitor on that PP1V_PRIM. I will try to test with ESR meter (tomorrow maybe). Thank you for your support.
There is also a cluster of pins on U7800 that directly bond to this rail (R12, T12, etc.) - so U7800 is still a suspect.
Really interested to hear of your test results with the ESR meter. It is on my wish list. There is an excellent YT video on this topic and it is a no brainer to justify the purchase. Just scouting for a good quality one at a fair price.
There is also a cluster of pins on U7800 that directly bond to this rail (R12, T12, etc.) - so U7800 is still a suspect.
Really interested to hear of your test results with the ESR meter. It is on my wish list. There is an excellent YT video on this topic and it is a no brainer to justify the purchase. Just scouting for a good quality one at a fair price.
I don't know why, but I strongly believe that the problem is on R12,T12,U12..... of U7800 ic.
I've checked all capacitor under microscope. Usually bad capacitor is visible. I would be tempted to desolder the U7800.
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