Voltage rating of electrolytics in a Philco Model 20

5/3/2011 12:05:24 PMLou

Hello all:

I am working on a Philco Model 20 restoration.

Does anyone know which caps in the power supply are electrolytic and what rating should I use? I think at least 300 V for the 1 uF and 1.5 uF caps. Is the 0.13 uF cap an electrolytic?

Thanks for any info
Lou

5/3/2011 12:57:28 PMWarren

The Philco part number is 4235 all voltage rated at 1200 volts. None are electrolytic. See this link.

http://www.philcorepairbench.com/metalcap.htm

paper Filter Condenser Bank Specifications

5/3/2011 2:41:46 PMlou

Thanks Warren

Looks like I have shorted caps.

Thanks for the info!!!!!!!!!!

Lou

:The Philco part number is 4235 all voltage rated at 1200 volts. None are electrolytic. See this link.
:
:http://www.philcorepairbench.com/metalcap.htm
:
:paper Filter Condenser Bank Specifications
:
:

5/3/2011 3:12:54 PMLou

PS I have 600 volt rated units on hand.

Would these do? Is the high voltage ( 1200 V) necessary? I do not see why?

Thanks Again

Lou

:The Philco part number is 4235 all voltage rated at 1200 volts. None are electrolytic. See this link.
:
:http://www.philcorepairbench.com/metalcap.htm
:
:paper Filter Condenser Bank Specifications
:
:

5/3/2011 5:40:48 PMEdd

Sir Lou. . . . .

After analysis of the specific in circuitry use . . . I'll now explain it to you this way.

The one unit wayyyyy down on the bottom of the totem pole . . . effective voltage rating wise . . . would be the
.13 ufd unit between Can terminals 2-6 which, is shunting and parallel resonating with the filter choke.

Then the 1.5 ufd unit that is between Can terminals 1-3 is receiving the lowest B+ . . in the order of ~200VDC or less.

The 1 ufd unit that is between Can terminals 1-4 is reciving the second lowest level of B+.

The most voltage available, will be impressed on the first input filter capacitor which is the 1 ufd unit that is between Can terminals 1-2.

Now with all of the use of modern plastic/styrene/polypropylene/polyethylene dielectrics on new generation replacement capacitors I can certainly see their use at your voltage ratings curently on hand for their replacement.

That . . . in being compared to the old kraft paper / aluminum foil construction of days past.

The worst case would be that input capacitor, but that should be no problem due to the mandated slow rise upwards of the B+ from the filament warm up time of the 80.

The one exception might be a post "rug rat" kiddo coming upon the running set and playing on-off-on-off-on off with the power switch.

Now having a warmed up set and your hitting turn on at a positive / or / negative peak node threshold . . . . is the onliest way I could see a turn ons transient rising even somewhat close to that voltage spec even for just a milliseconds instant.

Aside . . . .

(I think that you well KNOWS that very-very- rare timing condition when you hit an incandescant lamps wall switch at JUST that very critical timing of a peak node.)

The other filters down the line would have the in line inductive buffering time constant of either the power choke or speaker field coil . . . . isolating them.

Thassit . . . .

73's de Edd

:PS I have 600 volt rated units on hand.
:
:Would these do? Is the high voltage ( 1200 V) necessary? I do not see why?
:
:Thanks Again

:
:Lou
:
::The Philco part number is 4235 all voltage rated at 1200 volts. None are electrolytic. See this link.
::
::http://www.philcorepairbench.com/metalcap.htm
::
::paper Filter Condenser Bank Specifications
::
::
:
:

5/3/2011 7:58:31 PMcodefox

I really don't see why anything would need more than 600 VDC capacitors in these early sets. Only exception I can think of is any caps across the plates of the output transformers to prevent undue oscillationscfthat were not dealt properly in the preceeding circuits. These were often rated at 1000 volts or more.

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:Sir Lou. . . . .
:
:
:After analysis of the specific in circuitry use . . . I'll now explain it to you this way.
:
:
:The one unit wayyyyy down on the bottom of the totem pole . . . effective voltage rating wise . . . would be the
:.13 ufd unit between Can terminals 2-6 which, is shunting and parallel resonating with the filter choke.
:
:
:Then the 1.5 ufd unit that is between Can terminals 1-3 is receiving the lowest B+ . . in the order of ~200VDC or less.
:
:
:The 1 ufd unit that is between Can terminals 1-4 is reciving the second lowest level of B+.
:
:
:The most voltage available, will be impressed on the first input filter capacitor which is the 1 ufd unit that is between Can terminals 1-2.
:
:
:Now with all of the use of modern plastic/styrene/polypropylene/polyethylene dielectrics on new generation replacement capacitors I can certainly see their use at your voltage ratings curently on hand for their replacement.
:
:
:That . . . in being compared to the old kraft paper / aluminum foil construction of days past.
:
:
:The worst case would be that input capacitor, but that should be no problem due to the mandated slow rise upwards of the B+ from the filament warm up time of the 80.
:
:
:The one exception might be a post "rug rat" kiddo coming upon the running set and playing on-off-on-off-on off with the power switch.
:
:
:Now having a warmed up set and your hitting turn on at a positive / or / negative peak node threshold . . . . is the onliest way I could see a turn ons transient rising even somewhat close to that voltage spec even for just a milliseconds instant.
:
:
:Aside . . . .
:
:(I think that you well KNOWS that very-very- rare timing condition when you hit an incandescant lamps wall switch at JUST that very critical timing of a peak node.)
:
:
:The other filters down the line would have the in line inductive buffering time constant of either the power choke or speaker field coil . . . . isolating them.
:
:
:Thassit . . . .:
:
:
:
:
:73's de Edd
:
:
:

:

:
:
:
:
:
:
:
::PS I have 600 volt rated units on hand.
::
::Would these do? Is the high voltage ( 1200 V) necessary? I do not see why?
::
::Thanks Again
:
:
:
::
::Lou
::
:::The Philco part number is 4235 all voltage rated at 1200 volts. None are electrolytic. See this link.
:::
:::http://www.philcorepairbench.com/metalcap.htm
:::
:::paper Filter Condenser Bank Specifications
:::
:::
::
::
:
:

5/4/2011 3:55:27 PMLou

Thanks Edd

So again it begs the question..

Why would Philco use 1200V units in thios application? Is it because they made a "generic" can type unit , useable everywhere??

Thanks for your patience with my curiousity

Lou

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:Sir Lou. . . . .
:
:
:After analysis of the specific in circuitry use . . . I'll now explain it to you this way.
:
:
:The one unit wayyyyy down on the bottom of the totem pole . . . effective voltage rating wise . . . would be the
:.13 ufd unit between Can terminals 2-6 which, is shunting and parallel resonating with the filter choke.
:
:
:Then the 1.5 ufd unit that is between Can terminals 1-3 is receiving the lowest B+ . . in the order of ~200VDC or less.
:
:
:The 1 ufd unit that is between Can terminals 1-4 is reciving the second lowest level of B+.
:
:
:The most voltage available, will be impressed on the first input filter capacitor which is the 1 ufd unit that is between Can terminals 1-2.
:
:
:Now with all of the use of modern plastic/styrene/polypropylene/polyethylene dielectrics on new generation replacement capacitors I can certainly see their use at your voltage ratings curently on hand for their replacement.
:
:
:That . . . in being compared to the old kraft paper / aluminum foil construction of days past.
:
:
:The worst case would be that input capacitor, but that should be no problem due to the mandated slow rise upwards of the B+ from the filament warm up time of the 80.
:
:
:The one exception might be a post "rug rat" kiddo coming upon the running set and playing on-off-on-off-on off with the power switch.
:
:
:Now having a warmed up set and your hitting turn on at a positive / or / negative peak node threshold . . . . is the onliest way I could see a turn ons transient rising even somewhat close to that voltage spec even for just a milliseconds instant.
:
:
:Aside . . . .
:
:(I think that you well KNOWS that very-very- rare timing condition when you hit an incandescant lamps wall switch at JUST that very critical timing of a peak node.)
:
:
:The other filters down the line would have the in line inductive buffering time constant of either the power choke or speaker field coil . . . . isolating them.
:
:
:Thassit . . . .:
:
:
:
:
:73's de Edd
:
:
:

:

:
:
:
:
:
:
:
::PS I have 600 volt rated units on hand.
::
::Would these do? Is the high voltage ( 1200 V) necessary? I do not see why?
::
::Thanks Again
:
:
:
::
::Lou
::
:::The Philco part number is 4235 all voltage rated at 1200 volts. None are electrolytic. See this link.
:::
:::http://www.philcorepairbench.com/metalcap.htm
:::
:::paper Filter Condenser Bank Specifications
:::
:::
::
::
:
: