Hello, I would like to present a huge post but I am not very good with this so I will go straight.... First of all, I am from Cuba and the problems that might seem small here are enormous.... I have gotten an Amd R9 270 (which is an AMD edition, not Asus, not MSI) I got it super cheap... it initially did not show video signals... so I disassembled it to see if I could repair it using my own method (big mistake) Well anyway... I identified 1 MOSFET as short so I changed it... then I did some measurement tests and absolutely everything within the green zone marked me as short, both the caps and the coils... and That obviously can't be... I measured the other MOSFETs to find out if any others were damaged but I didn't find any more... and I didn't know what to do... I hope to get some answer.... Without further ado, Greetings colleagues...
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remove all mosfets and check for short. or use miliohmmeter to check for shorted mosfetComment
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Thanks For Reply...I already did that and I still get shorts in the vrm area... I'll measure with milliohms to see if I have another result... now the main problem is that I don't have a way to replace a MOSFET that was in short... I don't have access or way to acquire new...Comment
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Hello everyone.
Someone brought this poor hp in.
All power rails had normal resistances so i turned it on. Instant power cutoff...
First mosfet was shorted so replaced it...
After that I have tryed to start since no short was on the main power rail. the CPU middle dual mosfet heated up and protection shut down the laptop.
After investigating i have found that when the mosftet turning on then the mostfet got instantly hot (not the CPU)
Removed the faulty mosfet. -> now laptop turns on CPU mildly gets hot but laptop gives the common 5 long 3 short LED... -
Hi all,
I have recently picked up this Dell OEM Nvidia GTX 750Ti 2GB Video card. Its an old card I know but still wanted to get it working if possible. The problem is the following:
- Put the card in my testing motherboard and start running Heaven benchmark
- Benchmarks seems to run smoothly up until half way then the motherboard completely shuts off immediately
- Try to start it again and I get a slight move from the PSU fan - a clear short
- A little troubleshooting later I find one shorted Mosfet - Replace them both - short is gone
- Put the... -
Hi,
My laptop went dead and after checking ,the main 19 volt power rail was shorted. After some checks i could identify that a high side vcore mosfet was shorted.
I replaced the mosfet and now the white powerled is present , fans start spinning but capslock shows the famous 5 long and 3 short code.
I checked the vcore voltages after replacement and i get for all 1.01 V so means for me that the driver is still working of the replaced shorted mosfet. On the Nvidia i measure around 0.8 V after the mosfets.
I did voltage injection on the cpu with 0.7V and i have a current... -
Hi all.
This notebook was showing no signs of life.
I removed the FH52M LA-J891P mainboard and found that there was 19V at the DC jack.
However there was zero volts on the two PRB2 and PRB46 resistors immediately after the two polarity protection MOSFETs (PQB11 & PQB12).
If I remove the PQW1 MOSFET, the 19V rail starts working, and I can turn on the unit - at least I get the fans, and the power light comes on, when I simulate the power button being pressed. No display.
I tried replacing the MOSFET with a new one, but again no voltage on the... -
it is 3+2 vrm
vcore high side mosfet (AON6380) shorted when turned on instatly killed the processor (i5 7400)
gate drive chip (NCP81166) also gone.
any suggestions before replace mosfet and gate drive chip? what if I replace 3 high side mosfets with more current capable mosfets?
odd question:
what if I put two silicone diodes series in forward way? assume each diode 0.7v drop and total of 1.4V. vcore not exceed this but can protect cpu from direct 12V hit from shorted mosfet ?...
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