Part 30, Philco's interesting tone control.

OK, Philco hides two capacitors in the tone control body. A .09 and a .003 MFD. I had to use the heat gun to get the waxy tar or tarry wax out of it. Also the philco universal replacement for the bakelite block cap number 7653-C is actually incorrect. The universal cap is a 7653-DG and it's made BACKWARDS to what you really desire to have.

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People & Blogs

Tags:

• philco antique radio repair
• 1933 16B
• Philco tone control
• bakelite block capacitors

[AllAmericanFiveRadio]

I was looking at a drawing of a 1930s radio and I was tracing a wire in the power supply. In the drawing it went from the positive side and it weaved its way around to the negative side. That's right a direct short. Of course that's not the way it was really wired. Glad you pointed out to everyone that you are going to find errors with the documentation sometimes.

[Lockemeister]

I guess the replacement bakelite block Philco made was not as universal as they thought!

Another thing to watch out for is the negative floating B - . The 10 MFD cap floats the B- voltage for some sort of bias. The circuit has to be carefully ohmed out to make sure the 8 MFD caps which are part of the Pi filter network do not go to ground!

[joernone]

This type of potted tone control setup is found on many of the old Philcos. It's nothing more than another bakeite-style cap holder.

Recommendation: Don't bother re-potting. It's not needed. Just insulate the cap leads, place them inside and solder them in place...just like you did with the bakelite blocks.

You're doing great. Stay the course.

Regards,

John

[Lockemeister]

I ended up potting it with GE Silicone II. Mainly because the interior of the cap is visible. Now, when the silicone cures, I can install it and keep going. I'm starting to see light at the end of the tunnel and hopefully it's not a locomotive.

[daheick]

YA I had a simular problem with a bakelite block in a philco model 60. It said the 2 capictors went to ground. after I hooked it up like that the radio didnt work. turns out the one cap goes to ground and the other jumps between the other two lugs. Good thing for scmatics.

[simplertimes1]

Good tips. Nice job.

Wayne