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IIfx Power Supply Repair / Maintenance Questions

Posted by: campbellashe on 2026-03-23 16:06:20 I've come upon a IIfx and am working on fixing it up. The PSU is the SONY CR-45S (699-0393). The PSU worked briefly -- before my C1 capacitor issue for which I'm waiting on my Digikey order -- but had a lot of rust on the grille and inside the case. I've taken it apart and I'm using Evapor-Rust to fix the enclosure. My goal is to scrub it and paint it once the rust is off. The PSU itself looks okay without rust damage. I have a few questions: 1) Should I recap the PSU -- I see there is a kit by Console5 for my PSU -- but can't find any online videos reviewing a recap or maintenance of the PSU. 2) If recapping; to recap the small logic boards do most desolder them from the main board first and then recap? There appears to be two small logic boards off the main board 3) Should I replace the fan (92mm) (Panaflo FBK-09A12H - DC 12V, 0.2A) -- with a Noctua fan? mine is dirty but cleaning up nicely 4) Anyone have luck replacing the small LED light of the enclosure -- mine is rusted a bit -- I can't get it off the enclosure easily -- any tricks and recommendations for removal and replacement.... Here is the rust on the enclosure: Here are the innards and the small logic board: This is the small LED passing through the PSU front enclosure. Thanks for any help or suggestions.

Posted by: ObeyDaleks on 2026-03-23 17:26:18 The 699-0393 is significantly quieter and more rare than the 0389 or the Aztec, so if it was me, I would recap it. If recapping, I would definitely desolder and recap the daughter boards. Those small caps are more prone to failure due to drying out or leakage. I would not replace the fan. You can lubricate the bearings, but you will be hard pressed to find a better fan in terms of CFM/noise. Never tried replacing the LED but I’d assume any off the shelf led would work fine. Personally, I like the faint glow of the old LEDs better.

Posted by: s_pupp on 2026-03-23 18:09:08 I removed the boards of mine to recap them. The fan cools the entire computer, and I woudn't replace it with one that focuses on minimizing noise, as tempting as it is to do so. I have no recollection at all of what I did regarding the fan.

Posted by: jmacz on 2026-03-23 21:09:50 I also removed the boards. My LED came off rather easily as the plastic holder was cracked. I replaced the LED and hot glued it in place. Could have 3D printed a replacement holder but opted for the hot glue. If you running with only one card, you might get away with a Noctua but if you plan on adding more cards, you should leave the stock one.

Posted by: campbellashe on 2026-03-28 15:10:10 Full recap of the PSU completed. Mitigated the case rust with evaporrust and repainted it. Reassembled and working great; I was able to salvage the LED. Kept the fan -- after cleaning works great. Created a recap guide for the PSU as well (PDF included). Used fantastic link to Recap list found here: https://tinkerdifferent.com/resources/macintosh-iifx-sony-cr45-s-psu-capacitor-list.138/reviews.

Posted by: campbellashe on 2026-03-28 18:33:57 Okay. The PSU works and the computer works great. But... using the PSU to power the monitor does not... Any suggestions on this problem? I'll open it back up and check my connections again.

Posted by: jmacz on 2026-03-28 22:43:57 Check the output of the pass through port with a multimeter to see if power is getting there. If not, there’s a relay inside the PSU, usually an Omron part, looks like a rectangular box about 3 cm x 1 cm x 2 cm. Has four pins, one provides power to the passthrough port. Another is from the main power port. One is ground. And the last is 12v from the PSU’s 12v rail. The relay triggers when the 12v rail goes high, and provides power to the passthrough port. Check if the 12v is good or not.

Posted by: campbellashe on 2026-03-29 06:13:57 Opened up the case again this morning. Easier fix -- the CN1 connection from the main board was not connected -- oops.... I'm going to say it became dislodged. Working great now with full passthrough and soft power. Thanks for all the help. Fully functional IIfx restored to its glory. Now next project to create some more memory for it....parts on the way.

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