68kMLA Classic Interface
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| Macintosh SE: PSU recapping (regular or Low Impedance capacitors?) | |
| Posted by: Gregory K on 2015-12-23 12:25:12 Dear forum members, I'm going to recap a Macintosh SE Power Supply (made by Sony). The original capacitors are made by Rubycon, but I can't find any info on them. Should I replace them with "regular" capacitors, or will it be better to use Low Impedance capacitors? I would appreciate any info. Thank you!    | |
| Posted by: uniserver on 2015-12-23 14:07:53 just replace them with panasonic 105c and you will be all set... | |
| Posted by: techknight on 2015-12-24 07:03:14 Low esr is a necessity. Its a switching power supply. High esr caps will run warm and lead to an early death. | |
| Posted by: uniserver on 2015-12-24 07:50:47 well considering what is in there is General Purpose 85c cap. | |
| Posted by: takimoto on 2015-12-24 10:09:46 When I recapped my PSU of SE/30,Capacitor shop in Tokyo(Akihabara) said some Voltage-Rating was eliminated.so you might not be able to find same capacitance-voltage capacitor.but you can use higher voltage-rating ones(ex. 16V -> 25V).Usually voltage-rating gets higher,body of capacitor gets larger,may not fit into board.but capacitor I got were slimmer than 1/4 centuries ago.They were all low-impedance and 105C but not that expensive ones. | |
| Posted by: Gregory K on 2015-12-24 10:54:51 Thank you very much to everybody for your informative answers! Since using Low Impedance caps in the PSU would improve a reliability of the Mac, I think I can replace ALL capacitors with Low Impedance ones, except the big capacitor (400V 620 uF), which will be replaced by Nichicon GL (400V 680 uF). Am I correct so far? Also, there are two 350V / 4.7uF capacitors in the high voltage section (please, see the picture, they are black coloured). Is it ok to replace these two high voltage caps with Low Impedance capacitors as well?  | |
| Posted by: techknight on 2015-12-24 11:30:36 only the low impedence/low ESR caps are needed in the output section. Regular caps are fine on the line section. Low ESR caps wernt used from the factory only if they wernt available, or they wanted to produce them cheaper. But using regular caps do shorten their life, as they heat up more from the ripple current induced from high speed switching. However, you can get cheap 85c caps and still be low ESR, or low enough to where the power supply currents wont affect it. But generally as a rule of thumb, the ESR has to be low.. | |
| Posted by: Gregory K on 2015-12-24 12:34:17 Great, thank you very much for your detailed and very interesting info! If you don't mind, I only have one more newbie question left: According to Panasonic EB series specifications, these capacitors provide "Hight ripple hight frequency (High Voltage)" feature. With this in mind, is it good or bad to use such capacitors on the Analog Board of Macintosh SE, considering that this board controls the CRT display? | |
| Posted by: techknight on 2015-12-27 11:43:44 Read this thread: http://www.badcaps.net/forum/showthread.php?t=1458 lots of good info in here and it explains it better than i could... | |
| Posted by: takimoto on 2015-12-27 19:22:30 Good thread but bit hard without figure.I found pdf's on Nippon Chemi-Con website. http://www.chemi-con.co.jp/e/catalog/aluminum.html good explanation in "Judicious use of aluminum electrolytic capacitors" in Technical notes. | |
| Posted by: Gregory K on 2015-12-31 08:23:16 Great, thank you very much for these links! Merry Christmas and Happy New Year! 🙂 | |
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