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suspected dead iMac G4 power supply - can it be repaired?

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my old iMac G4 17" 1.25GHz USB 2.0 (PowerMac 6,1) suddenly stopped working after I unplugged it for the first time in years to move it to another room. Now when I press the power button, nothing happens - no fan, no hard drive spinning, no lights or screen - nothing. Before I had unplugged it, it would power up just fine.

after disassembling the iMac, I discovered the 3.6V lithium PRAM battery voltage was low so I replaced that. No change. I've tried resetting the PMU, also no effect.

after digging up a service manual for this iMac, I followed some troubleshooting tips and found the small voltage test-points hidden on the bottom of the unit near the PMU reset switch. I measure no voltage on the 12VSLP test point - the service manual says this means the power supply is dead. I further checked the pins on the power supply connector itself and it seems there is no 12V DC output on the connector. I've verified 120VAC is alive on the PS and the single fuse that I can locate on the PS seems intact.

I know I can buy a replacement/refurbished power supply for this iMac, but before I do that I'm wondering if anyone here has tried repairing this power supply?

if so are there any likely suspect components on the power supply to check, or common failure mode that's easy to repair (& diagnose)? I'm game to replace any components on the power supply circuit boards if necessary, but I've not debugged a dead power supply myself before.

Edited by: iRobot ( )

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