• Acer Nitro 5 FH52M LA-J891P no display

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Acer Nitro 5 FH52M LA-J891P no display

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  1. Topic title should contain: the device's manufacturer, full model and the brief description of problem.
  2. Topic message should contain: the PCB marking code (required in case of hardware repairs), an extended description of problem, things you have checked/replaced/measured, your conclusions and the question. If you are not able to find the PCB marking code, please read THIS TOPIC. If you still cannot locate the PCB markings, please upload a clean, both-side photos of the mainboard - it is required to remove any films, modules or brackets possibly covering these markings.
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#1 Acer Nitro 5 FH52M LA-J891P no display

by sarino69 • 27 March 2024, 19:34
Hi everyone,

Acer Nitro motherboard FH52M LA-J891P Rev.. 1B
The laptop arrived with a short circuit on the main power supply line +19v
After measurements and a short circuit test it was discovered that PQZ2 (AON6962) and PQB11 was damaged. After removing it from the board, the short circuit on line disappeared.

once the components have been replaced the mainboard now starts but does not give any image on the screen.
the fans spin, the keyboard lights up but no image. if I put a USB stick with LED it doesn't flash. If I remove and insert the power supply I hear a beep. the battery has charged

I noticed that There is no voltage on PLG1 - +VCC_GT, the rest of the voltages on all coils are correct.
I tried swapping PUG1 with the other components on the board but the power doesn't come back +VCC_GT

any advice on what to try?
I haven't flashed the bios yet. It is possible that a corrupt bios does not activate +VCC_GT ?

Re: Acer Nitro 5 FH52M LA-J891P no display

by Google Adsense [BOT] • 27 March 2024, 19:34

#2 Re: Acer Nitro 5 FH52M LA-J891P no display

by Vogelek23 • 27 March 2024, 20:09
sarino69 wrote:it was discovered that PQZ2 (AON6962) (..) was damaged.
Unfortunately, it seems that the CPU is most likely fried. I had a number of these boards in my workshop and all the time, when the upper part of PQZ1-PQZ4 was shorted, the CPU was damaged as well.

sarino69 wrote:There is no voltage on PLG1 - +VCC_GT
This voltage starts up as soon as the integrated graphic's drivers are loaded - in your case the OS does not start at all so the lack of +VCC_GT voltage is normal.

#3 Re: Acer Nitro 5 FH52M LA-J891P no display

by sarino69 • 27 March 2024, 20:44
thanks so much for the explanation. so you think it is useless to load a new bios? Is there a way to check if the processor is dead? any measurements I can do?

#4 Re: Acer Nitro 5 FH52M LA-J891P no display

by Vogelek23 • 27 March 2024, 23:12
sarino69 wrote:so you think it is useless to load a new bios?
It is always worth to try something which does not involve spending the money - BIOS reflash is one of these things. Please do not forget to transfer the original ME region.

sarino69 wrote: Is there a way to check if the processor is dead?
Unfortunately, there is no 100% certain method to confirm a CPU fault rather than replacing it with the known working one. All you can do is to measure the resistance to ground at VCC_CORE rails (of course after removing the faulty transistors). If the resistance is below 2Ω the CPU is faulty for sure.

Re: Acer Nitro 5 FH52M LA-J891P no display

by Google Adsense [BOT] • 27 March 2024, 23:12
 This topic is marked as ARCHIVAL. Please only reply if your message contains the solution (Terms and Conditions p. 12.1).
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