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Hello all! I'm new to this forum and am beginning a restoration on my 1930 Philco Model 20 Baby Grand Consolette. Does anyone have any particular advice on this model? Its the first TRF set I've worked on and definitely the oldest. I removed the multi-section cap today and will begin the fun task of emptying it tomorrow. The speaker is in fabulous cosmetic condition but sadly appears to be locked up as the cone has no travel at all. The cabinet has a few cosmetic flaws but nothing serious. One leg was split but has been glued up and, once set, will be good as new. This is my first Philco but hopefully not my last. Seems to very well built and relatively easy to work on. I've done several AA5's and a big Zenith console but this set looks like a real gem! Again.. Hello all! and I'm happy to be here.
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Hi and welcome!!
I've got a bunch of 20's. Seems like it's the same old problems. Check field coil, audio driver transformer, primaries of the rf coils. Not uncommon to find some open windings along the way. The only one that is tough is the field coil. All the others can be repaired. Since you are rebuilding the filters make sure the input cap is the same value as original if not it will over heat the BC resistor. Rebuild the bakelite caps, check and replace as needed resistors and your be in good shape. The speaker comes apart so you may be able to fix it.
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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City: Dover, OH
Your speaker might be ok 'mechanically. It seems about all the speakers I have encountered from that era of Philco tend to develope stiff speaker cones. The paper looks great, but it has tightened up to the point where it will hardly move. I didn't believe my friend about them until getting a couple Philcos with those speakers in them.
No matter where you go, there you are.
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Some of the values in the multi-section cap are a bit difficult to find. Is it ok to use slightly higher values? I have done that without any problems for several other radios but like I said earlier this is my first "old" radio resto..What values should I be looking for in the aforementioned coils/transformers? I've done several radios already but I must admit that I'm still relatively new to the antique radio scene so some of my questions may be elementary..Thanks for the responses!
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The cap in the filter bank is the one across terminals 1 and 2 is the critical one. It needs to be only a few mf like no more than 5mf. The rest can be 10 or 20mf. The resistance of the coils should be very low like a few ohms. The transformer primary a few hundred ohms same with the secondary.
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 40
Threads: 2
Joined: Jul 2011
All the caps have been replaced, the resistors have been checked, wiring is all good. Powered it up on the variac and got nothing but very low level static. No volume control. No stations. Not even a hum. Just barely audible static. The 24's filaments are very unevenly lit as well (one bright, one really dim, one in between). Considering this is my oldest set and my first TRF.. I'm open to suggestions. Thanks!
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City: Clayton, NC
The tubes will vary in brightness even when the radio works properly.
1. Have you checked all your tubes?
2. Did you verify continuity in your transformers? Often they have a problem as described in this web site and must be re wound. Additionally many old sets are "lightning strike" victims and the antenna/rf coil will be open.
3. The output transformer that is mounted on the speaker is often bad. As is the feild coil.
4. Field is spelled field. Jeez. " i before e, except after c......."
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City: Roslyn Pa
Check continuity between the pins on the speaker plug. All should have continuity to each other.
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 2,353
Threads: 92
Joined: May 2010
City: Clayton, NC
Yes, good point, Terry! There are instructions about how here in the Philco site.
Posts: 7,285
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City: Roslyn Pa
I try to come up with one or so a year. I always screw up field too...
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 40
Threads: 2
Joined: Jul 2011
Thanks for the advice guys. I will do some checks and get back to you. Was also advised to check voltages across the whole schematic as well. Off to the bench I go!
Posts: 40
Threads: 2
Joined: Jul 2011
Sorry but this just came to me.. Is it possible to add an auxiliary input to this set? If so where exactly do I hook it up? I am building my own AM transmitter but a direct connection would be nice too. Done tastefully of course. Low profile. I can start up several hours of old radio shows on an mp3 player and stash it inside the console and let people ask "what station is that?"..
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City: Roslyn Pa
What you can do is use a mono jack w/three contacts. break the connection at the grid resistor of the 27 tube. The grid goes to the tip contact, the detector output goes to the switch contact and the ring is grounded when mounted.
There is a significant impedance mismatch as you are going from a high impedance grid to 8 ohms. Will work much better if you use a transformer to match this difference. An audio output transformer(tube type) or filament will do fine.
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 4
Threads: 1
Joined: Aug 2011
I also have a philco 20 but it's a cathedral. I just got it and i'm beginning restoration. you were saying the cone has no travel? mine seems to be the same way, but I think that's how they're made, they're not like modern speakers which have a better suspension. but idk, correct me if i'm wrong.
Posts: 7,285
Threads: 268
Joined: Dec 2009
City: Roslyn Pa
It definitely needs to move to reproduce sound. On these guys I'd take a guess and say about 1/8 of an inch at least.
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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