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Philco newbie with P-1891-WA console questions
#21

Hi Jeff,

First off, you are in the right direction, getting the Sams Schematic for the set.  Secondly, you are getting great advice (as usual) from RadioRich.

You are not going to find exact fit caps and you don't need to.  For example, "this 1000 cap. 50v 65deg.Celsius chassis mount tab capacitor" can be replaced by a 1,000 uF 50WVDC axial lead capacitor.  You may have to get clever in how the cap is mounted.  Due to new electrolyte formulations, these caps are often much smaller than the 50- 60 year old caps that they are replacing.

Electrolytic capacitors are generally rated for capacity in uF (microfarads) and in "WVDC" (Working Volts, Direct Current).  Electrolytic capacitors are generally polarized and installing them in the correct direction is vitally important.  Installing them with reversed polarity will lead to failure, sometimes spectacular failure, such as smoke and exploding caps, blown transistors, transformers and all sorts of mayhem.  The working voltage should be as close to the voltage applied to the cap, but never less than the voltage applied to the cap.  For example, for the main filter cap, the output of the power supply is 43 Volts, therefore the 50WV 1,000 uF cap is appropriate.

For C6 and C9, the 100uF 10V caps are likely 10 WVDC.  Look for a "-" sign on the cap (It is usually the can).  Seeing + and - signs on the cap indicates that it is a polarized cap as most electrolytics are.

The main exception to this is in the speaker system.  in a multi-speaker system, the large speakers are called "Woofers" and reproduce the lower frequencies.  The small speakers are called "Tweeters" and reproduce the high frequencies.  to direct low frequencies to the woofers and high frequencies to the tweeters, crossover components such as chokes (inductors) and capacitors are used.  The "Crossover" caps are generally "non-polarized".  Here, the capacity is important, as the capacity dictates the "crossover" frequency.  For example, C8 and C11 are across the 12" speaker, the "Woofer" (low frequency speaker), "shunting" or filtering out high frequency from the woofer.    This cap must be 50 uF 25V NP.  If this cap is not available, then one can replace this cap with 2 100uF caps placed in series with the 2 + terminals connected to the speaker and the 2 - terminals connected together to get this 50 uF NP cap.  Interestingly enough, the alternate speakers shown in the diagram have polarized caps across the woofer.  Observe the polarity if replacing the 50 uF NP cap with a 100uF polarized cap.

The 2uF cap in series with the "tweeter" (high frequency speaker) blocks low frequencies from reaching the tweeter, passing only high frequencies.  Again, here, the value of the capacitor determines the "crossover frequency".  This capacitor should be a non-polarized electrolytic or can be a 2uF non-electrolytic cap.

Hope this helps.

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55


Messages In This Thread
462ron - by 462ron - 05-11-2025, 08:27 AM
462ron - by 462ron - 05-12-2025, 07:26 AM
RE: Philco newbie with P-1891-WA console questions - by MrFixr55 - 05-31-2025, 07:57 AM
Jeffcon - by Jeffcon - 07-21-2025, 09:24 PM



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