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Philco 21 repair - Printable Version

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RE: Philco 21 repair - Simon Wa3uay - 09-20-2019

I knew not that the speaker was re-coned....you've all given me things to look into and try...
and I certainly want to come to K-town, thanks for the invite! Not sure I can or can't this time. It starts today, and I gotta work!
-Simon

RE: Philco 21 repair - morzh - 09-20-2019

If I am tight and it was re-coned it is a good thing: new cones sound better than the original, especially those from 20 as it used the solid spider instead of the 45RPM flexible one.

RE: Philco 21 repair - Simon Wa3uay - 09-23-2019

Radioroslyn,

I connected to a ground, (a lab cart which is connected to electrical ground), and most noise went away, but still 60 cycle.

Then, I checked resistance between tuning cap stator and ground, and got 4.5 ohms with VOM, and 4.2 ohms with VTVM.  That's not "20-50 ohms" so something amish there?

Now for the good stuff.  I disconnected the .09 across the filter choke, and NO HUM!  hear video:

https://youtu.be/ps6rPDlPOzM

The wire I disconnected went to the Mershon positive terminal.

SO, just one more question (as Columbo would say, but then leads to even more); will this thing run ok on the 120 volts ok without burning up the tubes etc., or what is a good check on that?

Chas,

You were spot on with your "fix the radio first, then clean it up" sage advice for the greenhorn, and I appreciate that.

-Simon

RE: Philco 21 repair - Radioroslyn - 09-23-2019

The resistance is right on the money so you're good there.
I would have no problem w/leaving the cap across the choke out.
The simple answer to the line voltage question is to measure the 2.5v heater voltage and use that as a guide the to determine the proper line voltage. If it's say 2.7v then maybe but if it's 3v or higher then use a variac to adjust the line to 2.5v and see what the line voltage is. Then if you like you can use a bucking transformer to drop the line down a bit.

GL

RE: Philco 21 repair - Simon Wa3uay - 09-25-2019

Very good Radioroslyn!
It looks like we are getting lucky here: on 120v line voltage the 80 tube heater measures 5.AC (+ a needle) on the VOM, and the rest, including the 45’s, measure 2.4. I’ve been running it on 110v thru a variac, but won’t need that anymore I reckon.

We did find original knob for the on/off switch (well, Ben did)

So, looks like we are good to go!

OK Ben, time for the cabinet! (No pressure haha!) -This is a Father/Son project, and it’s going to turn out ok, I think.

NEXT UP? We just won a local auction on a 19B, and it’s painted white.....I’m going to go pick it up

Thanks,
Simon

RE: Philco 21 repair - Simon Wa3uay - 10-10-2019

Here she is, cabinet by Benjamin sharp, chassis repair by me.  Appreciate all the help from everyone!  And it looks like this is just the start, we have other projects we are working on.

video https://youtu.be/JcWPun-pvCA

   

   

   

RE: Philco 21 repair - morzh - 10-10-2019

Looks very nice!

RE: Philco 21 repair - Simon Wa3uay - 10-10-2019

Thanks, morzh! May this thing live for another 88 years! And me too- lets see, that would make me 154 yrs old....

RE: Philco 21 repair - morzh - 10-11-2019

Should you live that long, you will start collecting and restoring iPhones.