HP66312 and Agilent6612 Power Supplies RIFA Capacitor Replacement - - Page 1
Forum section: electronics / repair

author: 11mrjones
author_rank: Contributor
timestamp: June 05, 2025, 06:21:26 pm
content: Hello All - I acquired, from EB auction, 2 power supplies, HP66312 and Agilent6612. For the 66312 I replaced a few on board fuses, resistors and one jfet IC and the noisy fan and all is good now with this unit. For the 6612, it was working well when I received it and all I plan to do here is replace the noisy fan.The question I have for both these is are do I need to replace the caps that are across the mains input, C308, C309, C370. (see schematic and pics attached). The caps and the layout of them is the same for both supplies. They all look like they are in good condition and thesupplies are both working fine now. I ask because they are all RIFA caps. Is it only the goldcolored RIFA caps that should be replaced (as I did in my 2 HP3478's)? Or are these RIFA's the newer vintage that are ok to keep as is?Markings on caps areC308,C309:1N0 M1RIFA Y2PME 289 MA40/100/56/C250v ~SHHello All - I acquired, from EB auction, 2 power supplies, HP66312 and Agilent6612. For the 66312 I replaced a few on board fuses, resistors and one jfet IC and the noisy fan and all is good now with this unit. For the 6612, it was working well when I received it and all I plan to do here is replace the noisy fan.The question I have for both these is are do I need to replace the caps that are across the mains input, C308, C309, C370. (see schematic and pics attached). The caps and the layout of them is the same for both supplies. They all look like they are in good condition and thesupplies are both working fine now. I ask because they are all RIFA caps. Is it only the goldcolored RIFA caps that should be replaced (as I did in my 2 HP3478's)? Or are these RIFA's the newer vintage that are ok to keep as is?Markings on caps areC308,C309:1N0 M1RIFA Y2PME 289 MA40/100/56/C250v ~SHC370:470N M LNRIFAPHE 820M275~ X240/100/56/C250 VACThanksVictor

author: pqass
author_rank: Super Contributor
timestamp: June 05, 2025, 08:14:46 pm
content: They look fine. I wouldn't bother changing them just because they're RIFAs.As to whether it's just the gold RIFAs that have problems... I don't know.But they're the only ones that I've seen that get the hairline cracks (see attached).

author: MarosD
author_rank: Newbie
timestamp: June 05, 2025, 08:24:39 pm
content: These are quite new.I serviced a many, many old equipment, especially tape recorders (Studer, Revox) and problems were only with caps in transparent epoxy, often with visible cracks, bulky. After powering up, caps just exploded to non-shorting way and a machine worked well (if the capacitor was not needed for circuit). Problematic was only to clean a machine inside)I also got many devices with newer RIFA caps and without any problems.

author: factory
author_rank: Super Contributor
timestamp: June 06, 2025, 12:45:37 pm
content: From another thread;Quote from: factory on February 03, 2024, 11:26:51 amDon't buy anything paper based, leave them to become obsolete, the only place they belong is the past.And yes the white PM... series fail the exact same way.David

author: 11mrjones
author_rank: Contributor
timestamp: June 07, 2025, 05:55:27 pm
content: Thanks all for your advice. Looks like I will replace the small white PM caps (c308, c309). Leaving the other alone.

author: 11mrjones
author_rank: Contributor
timestamp: June 12, 2025, 04:10:50 pm
content: Replacing caps with these- PH series per rec here, thanks.https://www.digikey.com/short/mh8r0zjd