Zenith 9S54 - Printable Version
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Zenith 9S54 - adamrobertg - 05-24-2017
Just picked up this Zenith, model 9S54. I loved the angular art deco cabinet (which needs to be refinished- I learnt a lot from redoing my Philco 38-8, so, that will help me there!). The previous owner had been a repair technician and had passed away. It looks like he attempted to work on it, was about to, or gave up, as the chassis was loose in the cabinet and 2 knobs were missing.
I think the radio was hit by lightning via the antenna. It appears that what I think is the antenna choke is burnt, also the antenna terminal plastic is half missing and the terminal itself is hanging out the back, but connected to the antenna coil still. The choke (or whatever this thing is), seems to have 4 terminals, one of which is connected to the antenna coil and a capacitor.
I haven't measured anything yet, but what do I replace this with? The antenna coil itself has no burn marks, and I don't see any elsewhere in the radio... but what else could have been affected?
The cabinet is pretty nice, just one big scratch in front but otherwise I know will look great refinished. The speaker is in good shape too. The rest of the radio looks fairly normal. Most capacitors are original, one is a replacement marked Philco. A tube has the date 1938 on it from a radio shop in NYC, and someone wrote on the chassis a date of 1945 (probably when that capacitor was replaced).
RE: Zenith 9S54 - KCMike - 05-24-2017
Hi Adam. I'm adding a schematic link to your chassis to help anyone looking to answer your questions.
http://www.nostalgiaair.org/Resources/465/M0025465.htm
RE: Zenith 9S54 - Arran - 05-28-2017
What you will need to do is confirm that the antenna coil is actually burned out on the primary side with an Ohm meter, as well as that choke. It may be helpful to find out what is supposed to be there and what is not, if that small coil/choke is supposed to be there then it was probably a wave trap of some sort, and if it is burned out you can just bypass it if the antenna coil itself is still good. In some sets they would wind the antenna coil windings for each band on the same form which can make replacement difficult, though rewinding a broadcast band primary is a possibility unless you can find a replacement from a parts chassis.
Regards
Arran
RE: Zenith 9S54 - adamrobertg - 05-30-2017
Thanks Arran, I found a photo of the same chassis and it does have the small choke there. I think it's on the schematic as an antenna choke, with one side going to ground. I didn't even think of the antenna coil being burnt out... And it does look like it has all bands on one coil. I will check it, but I wonder if this is the reason the set never got repaired 60+ years ago.
RE: Zenith 9S54 - morzh - 05-30-2017
If this is the choke 10, it is not a band coil, the #1 is.
Isn't it some form of the IF trap? It seems like it could be shorted if it is the trap, or, if desired, replaced with any 1mH choke.
RE: Zenith 9S54 - Arran - 05-31-2017
Mike is right, the parts list says that the choke is 1 millihenry (not 10 mh), which means that you can still find a replacement if you need to, but I would check that antenna coil primary too. I think the choke was intended as a wave trap, if it is burned out hopefully it acted as a fuse and saved the antenna coil primary from burning up as well since it connected closed to ground.
Regards
Arran