Thank you for your concern, before connecting the PSU to AMP, I let it work independently for several hours, all the output voltages are right, the drift is very small, and it looks very stable. So I confidently linked it to AMP, but nothing good happened... Just like the carbon I made 8 years ago, the PSU also exploded, and that time I replaced the damaged part and it worked fine. Thanks to your advice, I will go find an insulation tester to test each power supply. I should be more cautious.The PSU was tested today and luckily all worked fine except for -500V and +500V.Waiting for new parts and replace the wire with a higher withstand voltage rating.