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Philco 21 repair - Printable Version

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RE: Philco 21 repair - Simon Wa3uay - 09-11-2019

Team effort! My Son Ben & I

Well, the potentiometer checks out- I disconnected ground and got the variable 5K ohms, reconnected and it plays now- I don't have the 3 'compensating capacitors' adjusted correctly yet (is there a trick to that?), plus my workspace is very RF noisy and don't have a ground hooked up.  I need to try driving a ground rod.

Is there a way to fix the frayed speaker wires at the plug without tearing into the plug and replacing all the wire?  blob of epoxy?

   

Thanks,
Simon

RE: Philco 21 repair - morzh - 09-11-2019

Now having some prior experience with these, I would try to, after cleaning the frayed insulation, push the wire through the pins (while heating the pins with soldering iron). If it comes through.

RE: Philco 21 repair - Simon Wa3uay - 09-11-2019

There's a hot idea! will give it a shot thanks!

RE: Philco 21 repair - rfeenstra - 09-11-2019

Given the "crispiness" of the rubber under the cloth, it will break everytime the wire is flexed.  Are you sure you don't need to replace the wire?

RE: Philco 21 repair - morzh - 09-11-2019

Which would be my recommendation also.
I usually replace the whole thing, even though the brittleness will not lead to shorts, but hearing that crispy crackling sound when disturbing wires make me want to replace it.
This said, if one is bent on preserving the original, it is possible.

RE: Philco 21 repair - Steve Davis - 09-11-2019

Look here  https://philcoradio.com/library/index.php/shop-talk/techniques/replacing-speaker-wires-without-drilling-rivets/   

Steve 

RE: Philco 21 repair - Simon Wa3uay - 09-12-2019

Excellent, Steve; I tried to heat up and push through but wires must be kinked in there...now;
where to buy that cloth covered wire?
I fixed the fraying temporarily with electrical tape and checked for shorts, but want to do it right eventually.

EDIT: I think I will email sundialwire with my requirement and see what happens....

RE: Philco 21 repair - Simon Wa3uay - 09-19-2019

I don't know if I'm doing this right https://youtu.be/DFA_bP4S6yE
link to video - the sound I'm getting is rough; must be line frequency
I know I have a weak 24 tube, need to replace (it's about 3/4 mutual conductance)
One of the 45's is on it's last leg...but works (I think)
I really need to check that voltages are correct (on the tubes)

RE: Philco 21 repair - morzh - 09-19-2019

Try to switch off your fluorescent or LED lights if you have any in your house.

RE: Philco 21 repair - Simon Wa3uay - 09-19-2019

Tried moving it to another room, another circuit- same- there are florescent and LED around, but other AM radios work fine- but I do have a noisy rf locality, even being out in the booneys! what else could it be?

RE: Philco 21 repair - Steve Davis - 09-19-2019

Your 24 tube is probably OK 

Steve

RE: Philco 21 repair - rfeenstra - 09-19-2019

A question about the speaker: Has it been reconed? Has the center spider been replaced with an external spider? Given that the center spider is broken, is it possible that the voice coil is rubbing? Perhaps I missed a previous post that talked about the speaker.

RE: Philco 21 repair - morzh - 09-19-2019

Rfeenstra
If you listen to his video, it is 60Hz hum, pretty pronounced. Even if the coil rubs (from the picture yes, it has been re-coned) this would not result in that hum.

WA3UAY

From your text I am not sure where you connected the electrolyics: you only mention one re-connected; there should be two, one on each end of the coil.
And, you could possibly ditch that cap across the filter choke. Doesn't do much good.

Mike

RE: Philco 21 repair - Radioroslyn - 09-19-2019

Sounds to me like you either have some strong electrical interference from lights or modern devices. Or a open grid circuit that is causing modulation of the signal. Would try an earth ground connection to the chassis to see if that improves things. Another thing to try is measure the resistance from the tuning cap's stators to the chassis. Should see a low resistance like 20-50 ohms. If much more than that you may have an open secondary on your rf coil (s).
As for the cone typically what a rubbing cone will do is give distortion @ low volume levels and if rubs badly it will give you distortion @ all volume levels.
If your coming up the Ktown stop in a say howdy!

Terry

RE: Philco 21 repair - rfeenstra - 09-19-2019

I was listening to the distorted audio, not the hum. Hum would definitely not be caused by the voice coil! Listening to it again, is sounds like the audio is highly modulated by the hum. Definitely an electronic problem.