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.