Maintenance of deep-sea ghost GG5CP5Z computer can't be turned on

Maintenance of deep-sea ghost GG5CP5Z computer can’t be turned on

This machine is a second repair machine sent for repair by peers. The fault is that it does not start, and it can be started only after being repaired as required. The specific maintenance process is as follows:

“Machine model” deep-sea ghost GK5CP5Z

[Fault phenomenon] No boot.

[Maintenance process] The board number is GK5CP5Z, which is a single motherboard sent for repair by peers. Since there is no external equipment, we inform the other party that it only guarantees the startup, not the functional failure.

Location of DC charging port and common point Figure 1 The single board is not in a hurry to power on first. Check whether the resistance values of the major inductors on the motherboard are normal. After a dozen values, it is found that the common point is big and short, and the resistance value is 0000. First, check whether the MOS tubes of CPU and graphics card are broken down. If there are no tubes that are obviously broken down, add a voltage of 0.8V to the common point first. As a result, it is found that the core of the graphics card is hot, which is not necessarily the core hanging, but also the MOS damage.

First, lift the inductor supplied by the graphics card. After lifting it, it is found that the resistance of the MOS tube in the middle is abnormal. Remove the middle tube and measure the resistance of the common point to return to normal. It seems that only the tube is broken. Pick a MOS tube of the same model from the material board, install it and measure the resistance normally. When it is directly powered on, the current can run for more than 1 year, and the external display screen can also display it. Then the problem is solved.

Short circuit of common point resistance Figure 2

Video card MOS tube short circuit Figure 3

[Repair result] Because the customer didn’t send the shell, the function could not be tested. After communicating with the customer and agreeing to only repair the boot, the test was ok and sent back to the customer.