I recently had a rash of reboot events on my trusty old iMac G5 (1.8
GHz).
This has already had the logic board replaced, as these machines
had some bad-filter-capacitor issues... but this time it was the
capacitors in the power supply, not on the logic board, that
were bulging and leaking electrolyte.

It took an hour or two of catalog work to find low-ESR replacements
for the
nine low-V high-I filter capacitors in the power supply, in form
factors
that would fit the cramped footprint of the originals. So, I thought
I'd relate the parts list here, in case anyone else has need of such
info.

C40 and C52 10V 1000 uF
EKY-100ELL102MH20D

C45, C55 and C56 2200 uF 10V
UHM1A222MPD

C47 16V 1200 uF
UHE1C122MPD

C49 10V 3300 uF
UHN1A332MHD ** this is slightly larger diameter than the
original, but it fits **
UHZ0J332MPM **right size, but less voltage margin**

C59 35V 330 uF
ELXV350ELL331MJ20S

C64 15V 1000 uF
EEU-FC1E102B

These were all in stock at Mouser Electronics, if that matters.