Philco 89 bypass capacitor voltage - Printable Version
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Philco 89 bypass capacitor voltage - retiredinprescott - 05-27-2011
I'm working on a Philco 89 (code 123) and I'm ready to replace the 5 bypass capacitors in the metal can under the chassis (part no. 4). They are .05,.05,.09,.09 and .25 uF.
I have some capacitors of those approx values rated at 200V. Can I get away with that voltage? or do I need to get capacitors with a higher voltage?
Thanks,
Mark
Re: Philco 89 bypass capacitor voltage - exray - 05-27-2011
Yes and no
For #4 and #39 200v would suffice but for the other three you really should use 400v or higher.
Re: Philco 89 bypass capacitor voltage - retiredinprescott - 05-27-2011
Thanks for the help.
One more question, if I may, at the risk of showing my electronic ignorance....
There is a bakelite cap block no. 17 which has two 0.09 caps in it. One is labeled 17 on the circuit diagram while the other is labeled 29. It is unclear to me if I can use my 0.1uF, 200V capacitors to rebuild that block??
Thanks,
Mark
Re: Philco 89 bypass capacitor voltage - exray - 05-27-2011
Yes, on both caps. There's minimal voltage on both of those. Without doing math its probably about 20 volts or so. And 0.1 is fine to replace 0.09. Philco did some funny things like noting "99k" resistors instead of 100k because of poor factory lighting. I suspect that their choice of "0.09" was intended to mitigate reading errors between 0.1 and 0.01
Re: Philco 89 bypass capacitor voltage - retiredinprescott - 05-27-2011
Thank you exray. I can continue with my rebuilding now.
Mark
Re: Philco 89 bypass capacitor voltage - exray - 05-27-2011
Hi again, Mark.
Next time buy all 630v caps and this will never again be a question! A few cents more but at the price for shipping when you only need onesie-twosies you'll be better off in the long run.
Re: Philco 89 bypass capacitor voltage - retiredinprescott - 05-27-2011
exray Wrote:Hi again, Mark.
Next time buy all 630v caps and this will never again be a question! A few cents more but at the price for shipping when you only need onesie-twosies you'll be better off in the long run.
That's good advice and what I usually do. I happened to run out of my 630V caps and was scrounging through my supplies when I found a bunch of 200V and 250V caps.
That's what prompted the questions along with my limited knowledge of electronics.