Philco Model 20 Vacuum Tube TRF Radio Repair - 1930 - 93 Year Old Tube Radio - Part 2 [4K]

Part 2 - This 93 Year Old vacuum tube radio is a Tuned Radio Frequency or TRF design which pre-dates Superheterodyne radios in the market place. The first superhet was sold in 1924 according to wiki, but TRFs were still sold for a few more years to come.
This came to me via a friend and was owned by his Uncle who had intended to repair and restore it but never did get to it. Let's get her working.
See the checklist which appears when status changes, for tracking what is discovered that needs addressing in Red, followed by Green when resolved.
NOTE: This is not instruction, it is for entertainment for people like me who enjoy watching projects and the experiences gained. If you attempt to do any of the things in this video you are at your own risk. I am using special tech-bench safety equipment not detailed here so don't take for granted you can just plug these old items in safely without them being checked and repaired correctly. Check out the link below to Mr Carlson's Lab video below.
ACKNOWLEDGEMENTS AND REFERENCES:
[note: am in no way representing how these folks have shown doing these things - I don't even think they would approve.]
Schematics: NostalgiaAir.com, philcoradio.com
Frequency generator modification to add an inexpensive frequency counter: Thanks Tony B. for the video and description - it works very well! Here is the link to the xraytonyb video (he also demos it by doing an alignment):
• Tenma Signal Generator...
@xraytonyb
Thanks to shango066 for championing the approach of "fix it first", before mass re-capping. See shango066 for many examples of that approach.
@shango066
Awesome discussion of bench safety including variacs and isolation transformers by Mr Carlson's Lab (highly recommended):
• Tech Tips Tuesday, Iso...
‪@MrCarlsonsLab‬
Modification method for a commercial Tripp Lite isolation transformer for tech-bench use by Todd Harrison, his channel is called ToddFun:
• ToddFun.com: Isolation...
‪@ToddFun‬
Camera: Canon G7X Mark III
Mic: Rode Micro
Video Editing Software: Power Director
Video Editor: just me
People interested in the following topics may be interested in the subject matter of this video: 1930s radios, tube radio repair, tube radio restoration, vacuum tube radio recapping, Philco Radio, Philco tube radio, Cathedral radio. radio recapping, valve radio, Vintage Radio, TRF Radio, antique radio, old radio repair, vintage radio, rf coil repair, Philco bakelite capacitor replacement, shango066, mr carlson, jordan pier, buzz1151, jim burns

[@PeterDyall-bn7ut]

Great work, and thanks for explaining everything as you go.

[@PracticallyFixed]

Thank you.

[@warreneardley789]

This radio belonged to my brother in law. I bought it at his estate sale in hopes that it could be fixed. He repaired an old RCA I had during WW2 and now my son listening to the baseball games on it. Thanks.

[@PracticallyFixed]

Thank you sir! It was my pleasure to fix your RCA 56X3 for him and am really enjoying working on this Philco. I appreciate getting the opportunity and thank you for thinking of me when you got it. I still have a lot to do on it, but my wife has me doing some overdue chores. Thanks again for the kind note!

[@robertcrawford7052]

Thanks for the video!. I have one of these also but it is the "Baby Grand Console" version. When I was a teen in the 60s, I saw a bunch of stuff sitting on a customer's front porch. I knocked on the door (they were early risers) and asked about it. He told me he was giving that stuff to the Good Will and I was welcome to take it. He was the original owner. Anyway, it is still in very good condition and I turn it on and play it occasionally. It has NOT been restored, but still works fine. I use variac and ammeter to monitor it when I do this.

[@PracticallyFixed]

Hello Robert and thanks for the comment. That is a great story, and from the original owner! Glad you are taking such good care of it. Post a video of it sometime! Thanks again.

[@mikeerstad3705]

Thanks for the Video.....I have a 1930's Grebe AH-1 TRF.....works good enough, could be a touch clearer, but just didn't want to touch it... Nice Job on the repair of the coil....super fine wires!!.....

[@PracticallyFixed]

They are tiny indeed. Thanks again.

[@danielconant749]

Hi, I have a few Philcos I have restored that called for a fiber wrench but I used a metal socket covered with tape as there was 150 volts on the compensators. Now I know how to make my own thanks to your idea. I have a Philco 89 that had a coil problem but started out looking like silver mica disease (popping and crackling). Turned out a bad spot on outer coil like yours. I was not able to save mine as there were several green spots. So I removed the wire and that plastic spacer and found green spots underneath. So I rewound both coils. Radio worked great after that (whew!). Turns out that plastic spacer turns acidic and that it what is doing the damage. I have a wire in my shop that is connected to a ground rod driven in the ground outside of my house. Hooking that to the chassis or ground terminal of the radio antenna just about eliminates the electronic noise. Keep up the good work.

[@PracticallyFixed]

Hi and thanks for the comment and suggestions. That is interesting about the plastic spacer, and the cardboard tube may also be a source of acidity. I plan on restarting the work on this unit soon - the last few months were very busy here. Thank you again.

[@yuriivanov12]

The name of your channel always makes me wonder if the repairing works are done or not 😂 Indeed, what does it mean - practically fixed? In my language it can describe a situation, when you've disassembled a radio, made the electrical part work, and that's it. So the radio is on the table, and the owner comes in and asks you - hey, is my radio ready? You say - oh yeah, it's practically fixed. The owner asks you - alright, I take it then. You - no, you can't. He - but you just said, it's fixed 😮😂😂😂

[@PracticallyFixed]

Ha. You got it! That was intended as a joke. Also, not throwing money at the problem if I can figure out how to fix what is there or using other parts and pieces. I spend some time troubleshooting to make it interesting for me and hopefully others. There will be more coming on this project (but the holidays here are busy with family). Thanks for watching and for the comment! Happy New Year.

[@hestheMaster]

Impressive job so far PF. Tough to do repairs with old eyes like on that coil.

[@PracticallyFixed]

Thanks Steve. Eye, knees, etc.; getting older is the pits, but as my late Dad used to say, it beats the alternative. Thanks again.

[@rsmrsm2000]

Amazing !
Please more videos

[@PracticallyFixed]

Thank you.

[@jimnewman5596]

Great repair on that coil. The TRF works really well picking up stations. It doesn't have AVC either.

[@PracticallyFixed]

Hi Jim. Thanks, looking back on it, it was fun using the needle to find the break. I think when I get an antenna wire not running past fluorescent lights and away from other noise makers in the shop it will perform pretty well. Got more work to do on it though. Thanks for the watching.

[@dangerousbrothersvintageel7494]

Really enjoyed your videos on this set , found your channel by accident, i have a 30s philco waiting to be worked on, Vintage American sets are not so common here in the UK, thats a beautiful set

[@PracticallyFixed]

Thanks for dropping by. Good luck with the Philco. I need to finish that radio up...

[@DERB_Seymour_Indiana]

Hey PF, nice sleuthing on that coil wire break. Amazing what one can see with the magic of magnification. Have to agree about tubes. Always been my motto that a good tech should not need a tube or transistor tester. Good job so far. :)

[@PracticallyFixed]

Hi Doug. Of course sometimes a tube's filament is gone in a AA5 so it needs to be changed, but yes even extremely weak tubes work well enough many times to get through the rest of the fix. Amazing this one was able to get a very weak signal through in spite of an open coil and extremely weak tubes. Thanks

[@donalddesnoo5303]

Have a working one I eliminated the original speaker w pm modern replaced the coil w resistor works well have the later s het as well both cathedrals and a parts chassis non working also have a baby clock w 4tube tombstone

[@mattk3118]

You have a lot of patience

[@PracticallyFixed]

Have had to learn to "just breathe" sometimes. Ha Thanks

[@sgath92]

I have a feeling inductor failure will be the biggest headache for the hobby a few decades out from now. Philcos are notorious for open coils but, I have seen enough in other brands particularly in sets stored poorly in unheated, high humidity barns/garages for years. Could be the canary in the coal mine. Hope not.

[@PracticallyFixed]

You may be right. Thanks

[@knifeswitch5973]

Where’d you go?

[@PracticallyFixed]

LOL thanks for noticing. Had to take a bit of a break for other things needing to be done. Restarted work on this project earlier this week an am currently redoing the wires on the transformer. Should be a few more days before I post a new part. Thanks again.

[@atwaterkent911]

That coil will fail at some point as the insulating material (acetate) will eventually corrode the coil in another section. This coil, and the other 2 such coils in this radio, needs to be rewound.

[@PracticallyFixed]

Are the power transformer, choke, field coil, audio transformers and voice coil windings at the time also coated in acetate? Or was it only the RF coils? Thanks

[@atwaterkent911]

Just the RF coils. Though early XFMRs were potted in tar which contained high levels of sulfer, so those can also corrode. This is mainly in Atwater Kent radios.@@PracticallyFixed

[@robertcrawford7052]

The last comment probably doesn't make sense. I was delivering newspapers early in the morning...😁

[@PracticallyFixed]

Ah now I understand! Thanks

[@BG-sl9lv]

unfortunately nothing but nasty talk radio on A.M. these days

[@PracticallyFixed]

Not enough music. I enjoy the games during baseball season though. Very nostalgic for me.