The PHILCO Phorum
Electrolytic Cap on Model 650 question - Printable Version

+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Electrolytic Cap on Model 650 question (/showthread.php?tid=24416)


Electrolytic Cap on Model 650 question - bobclausen - 06-23-2023

https://philcoradio.com/library/download/service%20info/wiring%20diagrams/vol1/split/Part87-Philco%20Wiring%20Diagrams%20Vol.%201.pdf

Working on changing the caps on this Model 650 and was wondering what voltage is required for Part #71, the 1, 2, and 3 mfd electrolytic.  As well is is ok to just use a non polarized film cap here. I have those on hand but would have to order the electrolytic caps. Thanks.

RE: Electrolytic Cap on Model 650 question - Steve Davis - 06-23-2023

Bob, I would definitely use film caps, they will practically last forever, not so for electrolytics.

Steve

RE: Electrolytic Cap on Model 650 question - morzh - 06-23-2023

The #71 cap's values, as long as they meet the sch values, are OK. You could use 10uF all around if you have this cap available already and do not want to buy more caps. 450V is my minimum voltage, 500V is preferred.
Yes you could use film caps, as Steve has already said.

The only cap you might want to have as close as possible to the value is the #78 an 8uF one.

RE: Electrolytic Cap on Model 650 question - bobclausen - 06-23-2023

Thanks gentlemen. I appreciate your knowledge and assistance.

RE: Electrolytic Cap on Model 650 question - radiorich - 06-25-2023

Hello bob,
Film caps are good choice because I need to replace the filter capacitors in my Philco 610b that restored about 20 years ago anyway this time I am using Film capacitors !

Sincerely Richard

RE: Electrolytic Cap on Model 650 question - morzh - 06-25-2023

I have always advocated the view that electrolytic caps are being badmouthed unfairly.
Yes, if using GP caps, which are higher impedance and not high ripple current-rated, they will go dry eventually. Not all, in fact, but mostly those in the very first rectifier filter position.
These caps experience high peak ripple and some significant RMS ripple, which, along with voltage/temperature eventually lead to their deterioration.

However, properly sized electrocyltic caps will last if not forever, then at least many, many tens of years. And typically they are cheaper than comparable good quality film caps.

I use Panasonic high ripple-low impedance 105C-rated caps. They are about $1 apiece in qty of 10+.
Another key is, of course, regular usage. Caps that do not get usage behave same as those in long storage and need re-forming due to developing thinning dielectric layer which is maintained when the cap experienced voltage across it.

This said, it is a matter of taste. I have a generous supply 22uF 450V caps from Panasonic, and I use them most everywhere in the rectifier filters. If I need 10uF, I serialize two 22uF.

RE: Electrolytic Cap on Model 650 question - radiorich - 06-25-2023

Hello Guys,
my go to years ago were sprague atoms now I use nichicon !

RE: Electrolytic Cap on Model 650 question - morzh - 06-25-2023

Any Japanese company will make good caps. Nichicon, Chemi-con, Rubicon, Panasonic.
I was searching for the highest ripple rating at 120 Hz, and found Panasonic to ve the highest, but of course there will be close matches or even better ones, undiscovered by me.
Just do not use no-names, or Lelon, or.....