LC III PSU Issue

[MegaImg]

I just finished recapping an LC III power supply unit (PSU). The Machine was not working because of the power supply unit (PSU). After recapping, measurement of all the power rails showed that not all of them are stable. Keep moving around, but not at the correct voltage. Any pointers on what to check on the power supply to try to get it working?

 

[Jockelill]

Are you measuring under load or with a loose unit? The PSU can only be measured reliably under load

 

[bobcat]

If you've done a recap of the board and didn't put on C22 "backward", I think will it affect the -5V rail.

LCIII Recap - Apple design fault -47uF reversed!

Hi, Am I the first person to discover this? C22 (the 47uF capacitor in the corner beside the power supply connector) on our LCIII has the + sign on the PCB on the negative capacitor terminal. This capacitor is between -5V and ground. The original C22 electrolytic on this board, and on...

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