[cparsons2391]

Hi everyone I am new here, but am glad to have joined the phorum!  

As my title state I am having issues with the electrolytic capacitors on my Philco 54. Number 41 on the schematic to be specific. I am not sure which side is positive and which is negative on the schematic. I have tried the capacitor both ways with mixed results.

When I had the negative side connected to filter choke and the Rectifier tube and the Positive side connected to the filaments the radio showed a dead short on my Dim bulb tester and the tubes did not light up.

When I had the positive side connected to filter choke and the Rectifier tube and the negative side connected to the filaments the tubes would light up, but the radio would be dead quiet and if I tried to measure voltage between the Plate and Cathode (P-K) the capacitor 41 would get very hot.

The only thing I had changed on the radio is the 3 electrolytic capacitors.

Here is a link to the schematics: http://www.philcoradio.com/tech/images/54.jpg and http://www.nostalgiaair.org/PagesByModel...013788.pdf

I hope this all makes sense.

Thanks guys!! I look forward to hearing from you!

[Nick3092]

I sometimes struggle with this, so don't take my advice as gospel here and wait for someone else to confirm what I said, or tell me I'm an idiot. But I believe the cathode on the rectifier is always the most positive part of the circuit. So you want the positive side of the cap connected to that.

Also, lytics don't like being hooked up backwards. I would toss them and get new ones, given that you have hooked them up both ways at this point.

[mikethedruid]

Yup, 'lytics aren't merciful. Once you hit them with a back voltage they're toast, so toss them and buy new. The positive side should go to the connection with one side of filter choke 40.

[cparsons2391]

Ok, great! I had it wired up right the first time. Thank you guys for the replys! I will replace with new cap to make sure everything is good.

My next question is why did capacitor 41 get hot when I measured Plate and Cathode (P-K) voltage?  

Thanks again for your help!

[mikethedruid]

The only answer I can give as to the cap heating is, if it was subjected to a reverse voltage it would probably have broken down the electrolyte and then the cap would behave like a resistor. In that case it would heat up. I have actually seen caps installed back wards explode with a loud POP splashing goo all over the stuff near them. Even if it was re-installed correctly, after the breakdown, it would still act as a resistor. That's all I can think of, unless the voltage rating of the cap was being exceeded.

[cparsons2391]

Here is an update:

I finally got the new electrolytic capacitors installed correctly and  the radio appeared dead. No tube filaments or anything.  So I started testing the tubes just to be sure of the quality and see if maybe a filament had opened up. When I tested the rectifier tube (25Z5) I found out that one side had shorted. When I tested the 25Z5 only one filament side would light and it would be super bright!

I managed to find another 25Z5 tube laying around and tested it. It had no shorts, but measured bad.  I went ahead and substituted it into the radio and the filaments light once again! Yay!

With the new rectifier tube I measured plate voltage on the 43 tube with no issues except I had 0 plate voltage.  

Tonight I am hoping to get some more testing done and figure out why I have 0 plate volts.

Thank you guys for reading my crazy posts!  8)

[mikethedruid]

We all come here with our questions and learn from those who have more experience. Happy to help. Keep us posted on your progress, you've got us all interested now.