Voltage Injection on 3.3v rail
I am repairing a laptop that has a short on it's 3.3v rail. I injected 1v on the rail and it was pulling 200mv but can't find any heat anywhere with thermal camera or alcohol. What else can I do to find what's shorted?
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Hi,
Try to repair a Thinkpad P72 EP720 NM-B723 MB with I7-8850H processor and N18E-Q1-KB-A1 (P3200) GPU with 6GB memory. Unfortunately there is noinfo what happened to the laptop. I got it disassembled with parts missing, like keyboard, battery.
Unfortunately I have no schematic available for me (requested in the sub porum) but got the boardview file.
Symptom: after connecting to the charger the power led light up for one-two second and switch off. After a couple secons the power led light up for half a second and switch off. No battery, no IO board, no... -
Hello everyone,
I recently picked up a laptop that was about to be thrown away to try to repair it. I've tested quite a few things, but I don't know where to look anymore. Could you please help me?
Brand: Asus Vivobook
Motherboard reference: x421da, Rev 2
Context:
The person who gave it to me mentioned it might have been exposed to water, but they weren't sure. After opening it up, I couldn't find any signs of water damage or oxidation on the motherboard.
The first thing I did was to connect the PC to a power supply: 19V stable and... -
Hello, I recently use PSU for voltage injection. I sent 1.2v 5A in big MSI motherboard and I felt nothing geting warm with my fingers (don't have termal camera). Finally chipset is dead (saw by using meter).
So voltage injection don't work, but it's big gamer laptop MB so, why not. But I used voltage injection again for small Asus Zenbook lapotp (14'). 1.5v 5A and I felt nothing again. Probably CPU/chipset dead because caps at reverse side are shorted to ground (0 Ohms) but I felt no warm. I used thermal probe and temps grew up for 4 degree C. Low for 7.5W ?
What's... -
Hi everyone,
I have a strange problem (for me) on an MSI GT70 2PE laptop.
When it's under heavy load, power goes steadily to the battery (for 2 or 3 seconds) then return to the charger. If I remove the battery it turns off.
The higher the load, the lower the voltage on the main rail. We go from 19.5V, PC connected to the charger but turned off (normal consumption of 0.06A)
On, when it draws 2A the voltage is 19.2V, then eventually collapses to 18.5V (and turns off) around 5A.
I removed the first 2 mosfets (PQ13 & 14) from the main rail, without noticeable change.... -
Hi,
I'm learning electronics(already have some basics) by fixing a FH52M LA-J891P rev1B. It come from an acer nitro 5. The charger was defaulting upon pluging. The 19V rail resistance is 0ohm (I believe that caps screw my measurement). When i inject 5A, I get a rail tension of 1.3V, and 0.8V vcccore.
Except the cpu, I cant feel anything getting warmer.
I believe that it is normal, because the cpu is "eating" half the power I'm imputing.
I dont know if the cpu is fried, because I did not remove the big capacitor on vcccore.
I believe that if the cpu was fried,...