Apple workstation 820-2337-A does not trigger repair

Apple workstation 820-2337-A did not trigger. A good G pin was found and replaced. The troubleshooting and maintenance is over.

Machine model: Apple Workstation 820-2337-A

Fault phenomenon: no triggering

Maintenance process: the customer sends the machine to have a look at the Apple console. Said it can be lit occasionally. More often than not, the machine doesn’t respond. I didn’t trigger successfully once.

Dismantle the machine (This guy is not easy to dismantle the machine. It seems that there are videos in BILI online). No drawings found. Then use the original method. The inductance and resistance of the two mainboards are basically normal. There was 3.3v voltage at the trigger. First, the power supply problem was eliminated and the problem was locked in the motherboard.

I found relevant information about the forum and said it very vaguely. However, I saw a general maintenance direction. There was no output voltage during the measurement, but there was 1.3V voltage at pin G. Find a similar one on the other material plates and replace it, then measure it and wait for 1.3 to come out. After the board is connected and powered on, the CPU fan turns, and the external screen is blank. The maintenance is basically over.

Apple workstation 820-2337-A does not trigger repair Figure 1.