Hello All,
I'm having trouble replacing the CPU VRMs on my 820-3662A. This board was crashing randomly and I know the VRMs are the usual suspect.
I removed all three of the VRMs but after I replaced them, only the Phase-1 VRM was working (it gets very hot, the others are cold). I get 1.29v on the VRM coil outputs, which appears to confirm that only one phase is operating.
To prove this I removed the VRMs for Phase 2 and Phase 3, then powered the board up. The VRM output is a 1.29 with only U7310 connected. I decided to replace the controller U7200 but it did not change the result. I've tried using FDMF6708 and FDMF3030 FETs and the results are the same. Right now I have only U7310 and 7320 on the board.
I replaced the VRM FETs on an 820-00138 board and had no problem at all. It's hard to understand. The FETs were purchased from a reputable North American supplier.
Just curious if anyone has had a similar experience or has any suggestions.
I'm having trouble replacing the CPU VRMs on my 820-3662A. This board was crashing randomly and I know the VRMs are the usual suspect.
I removed all three of the VRMs but after I replaced them, only the Phase-1 VRM was working (it gets very hot, the others are cold). I get 1.29v on the VRM coil outputs, which appears to confirm that only one phase is operating.
To prove this I removed the VRMs for Phase 2 and Phase 3, then powered the board up. The VRM output is a 1.29 with only U7310 connected. I decided to replace the controller U7200 but it did not change the result. I've tried using FDMF6708 and FDMF3030 FETs and the results are the same. Right now I have only U7310 and 7320 on the board.
I replaced the VRM FETs on an 820-00138 board and had no problem at all. It's hard to understand. The FETs were purchased from a reputable North American supplier.
Just curious if anyone has had a similar experience or has any suggestions.
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