Guide to Fixing Whatsminer's Power Supply

There have been previous requests for the circuit diagrams of Whatsminer's power supplies, but good documentation is hard to find. I came across an article on zeusbtc on fixing Whatsminer power supplies, and I thought I'd share it here in case anyone's interested. Let me know if you have any questions or need clarification on anything. 1. Power firmware update If there’s no voltage when you power it on by itself, you need to connect the control board to the power supply and update the firmware made for the control board. After you restart it and test, you should see an average voltage output from the power supply. 2. Voltage issues Start by unscrewing the power supply, pulling out the circuit board, and removing the fan. Use a multimeter to check if the output terminal’s positive and negative poles are shorted. If they’re not, see if you have voltage input. You typically measure this across the two pins of the bulk capacitor. Make sure the input voltage is around 420V; if it’s only about 300V, it means the PFC isn't boosting properly. You'll need to discharge the capacitor for safety before moving on. First, check for short circuits or solder issues on the control chip circuit. The VCC is what powers the chip circuit on the control board, so ensure that the VCC power supply is working fine. Check if the diode transistor in the VCC circuit is functioning properly; if not, replace it. But if you see the VCC voltage fluctuating after powering on, it indicates the VCC circuit might not be operational. The VCC is rectified using multiple diodes.