[BrendaAnnD]

This is a 38-34 set that I just got in tonight. I've been playing with it all evening. Even after I recapped the entire audio section, the best I could get out of it was a good waveform going into the output tube, but a very distorted (tons of harmonics) output that was several dB below the input.

I found the primary problem with the radio itself by accident: the dial lamp. Without it, there are no filaments on either the mixer/oscillator nor the output tube. Talk about your dial light being critical... sheesh. I will need to find a proper dial lamp for this set. The Philco part number appears to be 34-2150. Is there anyone out there that can give me the voltage/current of this lamp? If I can't find one, I'll end up modifying the pilot lamp circuit and use a resistor to complete the filament string and simply wire the dial lamp into the 6V supply and put a 47 in the socket.

Also, I'm working from a schematic for the Code 125 set, which this one is not. I need to find out the proper code so I can try to find the proper service literature. As of right now, I'm running the B+ from my regulated power supply, because there is no output from the vibrator supply (filters are leaky at the very least). I would like to get the right literature to start with before I crack that open..

   

[Ron Ramirez]

From Chuck's site:

34-2150 - 2.1V, 120 mA

[Chuck Schwark]

. . . . . and I was just gonna say…..  

Happy New Year Brenda.  Keep your side of the globe spinning.

Chuck

[BrendaAnnD]

Thanks Ron and Chuck. Happy New Year to you as well.

Here's something interesting, maybe Ron can shed some light on it. I went looking in Nostalgia Air for something closer to what I had than the 38-34 Code 125 that they list. I found something that looks virtually identical, the 37-34. Yet, the diagram and model number inside the cabinet definitely says 38-34, and the diagram matches the chassis. Color me somewhat confused.

[BrendaAnnD]

Think I found my explanation. Seems the 37-34 and 38-34 Code 121 use the same chassis. Do you have this packet, Chuck?

[Chuck Schwark]

Maybe factory had some leftover 37 version chassis' and used them 
for the early production runs in the new 38 model year?  

Philco was notorious for doing odd things with cabinets and innards.

Ron can elaborate or correct as needed.

Chuck

[BrendaAnnD]

Thought you might like to know, I have finished rebuilding the vibrator power supply for this radio. It seems to be working perfectly. 154 volts output under load. Looking at the output of the second filter cap, the DC is quite clean, just 0.2V of ripple/noise.

Ended up having to repair the antenna input coil. The radio was working, but the antenna trimmer had no effect, and touching the grid cap on the mixer resulted in huge amounts of hum. This put me on the trail of the open coil. Repaired that and now the trimmer works fine, reception is good.

Still need to replace the isolation grommets on the tuner sled, and do some repairs to the cabinet. I will also likely try to do some scrubbing on the chassis to clean it up. I will post pics as I complete the work.

[BrendaAnnD]

Remounted the PSU tonight, and modified the C- battery to use a single 3.3V cell. Radio is working very well now.

Yes, I still need to restuff the bakelite block. It just hasn't been my highest priority because of the relative difficulty of working on this particular block (holes are all soldered over)

Ordering the replacement RF sled washers tonight, then will start working on the cabinet. Still waiting on my dial lamps to come in.

   

[sam]

Brenda
what is the thing that the purple battery is connected to?  (looks like 3 cups)
sam

[BrendaAnnD]

Sam,

That held the old 1V carbon batteries that were used for bias. It was a cute idea, and certainly made it simple to change the batteries back when you could still get them.

[tom.seeger]

Thanks Brenda. I feel much better about the condition of my own work bench now after seeing the picture in your original post. :-)
Tom

[jerryhawthorne]

Tom, your right. Brenda does great work but I couldn't work in that much chaos. I showed that picture to my wife and she indicated she would no longer complain about my work bench! Mine is not very neat either.
Jerry
















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