I have finally completed my Philco Model 20 restoration including the cabinet.
I was not able to retain the original wood grain, but for my first major cabinet reconstruction I am pleased, even though it is not very close to the original radio.
I have posted a couple before and after photos. I hope I did that correctly.
Gary, That cabinet looks great! I tend to stick with plastic cabinets or wood cabs in good condition. The only thing I know about fixing a wood cab is to pay someone else! Joe
Sweet!!! You got the speaker grille cloth spot on! The sides look great. The grille on these is usually a total mess and you resurrected that also.
Do you have pics of the chassis also. If in a previous post, please send a link.
I have a 20 also (actually, I have 2). These are interesting sets as they don't work like later model superhets. Volume is controlled by shunting the antenna coil and biasing the RF amps. A properly designed TRF can give very good fidelity.
The audio interstage transformers have a way of the primary opening up. There are techniques for "bridging" the primary if this happens. If the primary is good, there is a technique for capacitively coupling so as to keep DC current off the primary. This may prevent a burnout and is supposed to greatly increase the fidelity. I have done so and believe that it does help. The link is here: https://philcoradio.com/library/index.ph...nsformers/
One of these days I am going to put a Radio / Aux switch into it.
Depending on the age of the set, there are 2 different versions of the speaker. For the earlier version, the "spider" (the part that holds the voice coil centered in the magnetic field) is like an inverted metal cap and is very inflexible. The later version which looks like one of those 45RPM record center hole adaptors (OK, you may have to be 70+ years old to remember those) is more compliant and provides better fidelity, especially bass response.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
I uploaded a pdf of the underside of the before chassis, which was very clean. When I started to work on this radio I took the time to understand the layout and added pin numbers etc. to the photo creating a useful map, similar to the original documentation. This pdf may help someone with their Model 20 restoration. Unfortunately, I didn't take any photos of the finised chassis. I will remove the chassis at some point and take a few pics to post here.
The main issue with this radio was the power transformer. The HV windings were open. So, I decided to disassemble the transformer and rewind it! I have attached a photo of the transformer after I removed the iron core. The rebuild of the transformer was successful! Looking back, I should have taken photos after rewinding, my bad.
I restored all of the tar filled condensers and the main power supply filter condensers. On this radio I learned how NOT to clean the dial scale! I had to get a reproduction.
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