LENOVO G50-80 laptop motherboard repair
The coding of this motherboard is ACLU3/ACLU4 UMA NM-A362 REV 1.0.
The problem with this device is that it does not work at all
Through a simple initial examination, it was found that someone, while trying to replace the charging socket, caused damage to the IO chip
Therefore, we replaced it and programmed it, replacing the charging socket with a new one, as well as replacing the network IC, because it was causing a short circuit on one of the paths of the 3-volt circuit.
After that, the device returned to work, but another problem began, which was that the device worked without displaying data on the screen! From here, another reform journey began
Before starting the repair process, illustrative (anatomical) pictures of all circuits and their voltage values and impedances were attached to facilitate the repair process.
We started the repair process by measuring all the circuits to show that they were all safe!
We then moved on to measure all the important signals on the BIOS chip, and they were present and intact!
Here, we moved to the general diagram of the motherboard, specifically the stages of the motherboard’s operation. Logically, we started from the stage after the appearance of the processor voltage, because it is actually visible, as is clear in the measurement process, in order not to waste time.
We started with the POWER_GOOD signal, which is called VR_REDY in this diagram, and through the process of measuring it on pin 70 of the IO chip, its presence and safety were revealed.
Then we moved to the next stage, which was to ensure the integrity of the PCH_PWROK signal, and it was intact as well!
Let us then move on to measure the SYS_PWROK signal on pin number 30 of the IO chip, to discover that it does not exist, and we must track it and try to find the reason for its non-appearance!
While tracking this defect, something unexpected happened! As you will see in the steps to repair this panel, we await your opinions, comments and analyzes about this strange malfunction and what is the scientific explanation for what happened from your point of view.
We wish you an enjoyable and beneficial viewing
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