[morzh]

This is the second 20 I am restoring, the first wa done 3 years ago and was the very first American tube radio I restored, a lowboy.

Now, after a perfunctory 10-minute checkup, and the premise that all caps have to go,

1. All resistors have to go, 50 to 100% up in values. But in 20 there are just 5 of them, common values and 1/2W is all that is required.
2. The wirewound reistor is fully good.
3. Both the choke and interstage audio xfmr are good.
4. I have done the speaker early this summer.
5. Some ground rivets are high in resistance, 10-12 Ohms which will need to be addressed.
I intend to try running a thick black-colored wire between those, this should be low inductance and will povide for a good groundung. Hopefully it won't create a loop as I will try to run the wire the shortest path fom Power supply (point 3 of the big resistor) two-prong, one to audio out, and one to RF.
Will see how it affects hum, should it exist of course.
That to me looks easier than re-riveting.


And lastly, the question I want to ask: yes I know the filter caps are typicaly repaced.
I also know Terry tends to keep those if they perform well.
Consideing those are huge fully potted paper caps (I remember they are ginormous) - what's the experts majority's opinion? Should I give them a test r should I ditch them no matter what?

[Radioroslyn]

Actually I just test them so I can give the set a try before I start the rebuild. Helps with troubleshooting the rest of the set. Usually I don't leave them in for the duration.
Terry

[OldRestorer]

Replace them Mike.... Better now than a redo later on.

Do you skip filter caps on my chassis?

At least they didn't blow up!

Kirk

[morzh]

Most of your chassis were recapped by you, I only did 1.5 (recaped one and half the other, the rest was done by you). But these filters are lytics, whereas 20 or 111 are plain paper.


OK, I will toss them.

[morzh]

Lifted the filter can.
Reisted a little; I warmed the panel up for a minute on Low by the heat gun, it got unstuck readily.

Soaked the tuning cap, cleaned the chassis.

Enough for today.
Considering I made chicken soup for my daughter (there you have it, young generation, it is not even fall and they already are having colds), and of course the others got on the action too, so half the pot is gone, shopped for groceries and about to spend an hour working on a side consulting project from my former job....they did not go in vain.


Speaking of groceries, while shopping for delies, I told the girl behind the counter she looks like the Fiona character from the "Burn Notice" series. She said I am the third person telling her that (she is a spitting image). I then told her she had to be Irish and she said laughingly "no, pure Italian".

[OldRestorer]

Fiona huh,
She is a hottie

I hate that Michael let his mom blow herself up in the finale!

Bad ending!

Ok go back to work

[morzh]

I did not see the end...she blew hersef up? That sucks. Though she was kinda dense..a bit.

[morzh]

Finished recap-recarb.
Would be it for testing, I have the filter block connected, though the can has not been cleaned yet but that is not needed for now.
However when starting on the chassis I saw the volume pot touched up, and I see the sectios have been swapped. The 250 Ohm section (the back one) is connected to GND and ANT, and the 5K section is biasing RF cathodes. The tell-tell sign, the GND strip is soldered to the back section. Should be the front one.

mañana....

[morzh]

Yesterday swapped the volume pot sections, soldered the tuning cap in pace.

Secured the filter block panel with shims so it does not short until I empty the can.

Checked tubes.

Put AC in, measured filaments, then inserted the tubes, plugged in the speaker, turned on, measured B+.

Then tried to tune....heard howling, some motorboating, and the faint local station.
Put the shield in, no reception.

Changed the 2nd RF tube, got good reception, cleaned and tightened the socket, cleaned the old tube's pins, put in, good reception, listening to the news now.

The dial is off....

Alignment tomorrow.

[morzh]

Aligned it, at 1400 kHz. The dial is still a bit off but I am not gonna fret over it.
Done.

The last thing is empty the can and put it back.

PS. there was a hum, came and went, depending on the chassis twisting etc.
I thought of those rivets, but ventually it happened to be some loose connections in the 27 tube socket.
Tightened, put some Deoxit on them with a cotton swab...gone.

I hope this is it...the can will wait for me to come up with a clean way of emptying it....the big bolt and heavy vice worked on 111 but still too much debris......

[morzh]

Well....this is the most dreaded part of any 20 reair for me.
Not recapping, not washing the tuning cap, not even rewinding an RF coil.

The can emptying.
The 111 technique with big bolt and vice for a wight does not work.

Tonight I did the same thing I did 3.5 years ago, heating and removing sections of caps with a bolt and large screwdriver.
The can is empty, tomorrow will by some laquer thinner (I am out of it), clean it inside a bit, and replace it.

Kirk did a great job on the cabinet, so this is the last radio I have to put together after visiting him this last weekend.

[Arran]

 Philco 20's can must have had more tar stuck to the inside, or had no liner, the 111's can must have been lined with fish paper with less tar. 
Regards
Arran

[morzh]

Arran

20's can does have liner. But it really adheres well to the can. Not sure why. This is the second one I have dealt with.

111 was really easy to gut compared to it and the liner was different. I think the blue paper kind.
In 20's case it is the brown kind, looks oil-impregnated, or it is oil absorbed from the tar.

[morzh]

I hope this is the last one....

I wrote before how when the chassis flexed the radio hummed.
I traced this to the 27 tube, when wiggle it, the hum would either disappear or come back.
I bent the panel's contacts, cleaned them, it seemed to stop.
Today it came back with a vengeance.

I soldered a wire and a lug to improve a questionable ground rivet on the tube's pin, no effect.
Then I wiggled the wires one by one and one of them did produce results; I thought it was bad connection....looked close.....the wire (factory sodering) had its end sticking out and touching the chassis.
The wire hapened to be one of the filament pins.
Cut the end, the hum disappeared.

....I was wondering why me gounding the Chassis rivet for the tube, the hum persisted. I guess 1 or 2 Ohms did not matter much.

I am gonna leave that Ground wire in place though

[Ron Ramirez]

Great catch, Mike! I think several of us have caught joints that were never soldered, factory wiring errors, etc. It just shows that the people who built and tested these radios as they came through the assembly line were not perfect and made mistakes. I think it is a reminder that no one is perfect.