Repairing an unstably running Apple eMac by replacing CPU power converter capacitors


Put down the eMac onto it's screen surface. Unscrew the cover of the memory compartement (1 screw). Remove the cover. Unscrew the two clear plastic feet. Unscrew the seven big screws, one at the bottom side, two on each other side

Lift off somewhat the big white plastic housing and pull out the cable connected to the power button. Remove the housing completely.

Remove the four screws holding the bottom part of the steel housing of the system board. Remove the steel housing bottom by tearing it off with a screwdriver.

Unplug the fan power supply. Remove the two screws attaching the fan frame on the left.

Remove the two screws attaching the fan frame on the right.

Cut the cable tie holding the monitor video cable.

Leave the fan frame hanging at the right side.

Unplug the monitor video cable.

Unscrew the system board frame, begin with the marked ones.
Note the eight bad capcitors on the system board, all circled red.

These are the six electrolytic capacitors of several on board voltage converters. Those are of inferior quality, have a bumped up top and there is even one where the electrolyte came out.
They all need to be replaced by a high quality, low ESR (Equivalent Series Resistance), high temperature replacement. I put 2200uF, 10V, 105°C, ZLH from Rubycon.

Continue unscrewing the system board frame.
Unplug the speaker, mirophone and what ever else is there.

Continue unscrewing the system board frame.
Unplug the speaker, mirophone and what ever else is there.

Unscrew the rest of the system board frame. Now you can pull the system board frame off of the rest of the eMac.

Unscrew the hard drive holder from the system board frame. There is a screw on both sides of the drive.

Remove the hard drive holder and unplug the IDE and the power supply cables.

Now all of the solder pads of the defective capacitors are accessible. Unsolder them and put new ones.

Unsoldering is not that easy, as the main board is a multilayer board with big area power supply layers. A lot of heating power is needed to melt the solder. Use a temperature regulated soldering iron with at least 50-80W and set the temperature to 400-450°C. Don't use excessive force if the solder does not melt sufficiently. Otherwise you may destroy the hole metallization.

Use fine desoldering braid to remove the solder from the holes when the caps are removed.

Finally reassemble the eMac by applying the disassembly steps in the reverse order.

I successfully repaired 3 eMacs this way, which are working properly again, now.

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