I have a 42-380 (who doesnt). I am a newbie, and once had Ron do a 41-608 for me (still going strong..)
I recently finished repairing a Delco 3205 (32 volt) and taught myself a few things about working on a tube radio. I have Delco 32 volt generators, hence the interest....
NOW, getting on with it...I am working on this 42-380. I was given one, and after taking out the chassis, guess that the electrolytics went, shorted out the xformer, and nearly caused a small fire in it. Suffice to say good for parts. I got another chassis and after cleaning the tube pins, sockets, and double checking for obvious problems have powered it up successfully, and all tubes are OK, and I have 60hz hum, if I probe the vol switch. After poking around some more, I find that the screw adjustment on this rf can is all the way up. I discovered that if I touch that screw with a finger, I get a buzz as if its trying to use me for an antenna, but no stations come in.
I will put new electrolytics in and recap for the first time. By doing so , do you think I'll be closer to a working radio?
Why does that IF can act as if I'm the antenna when touched?
Is it usually the electolytics that prevent it from recieving stations?. The Audio output acts OK, or I would not have heard anything playing with volume, tone and touching the pins on the 41's.
trying to understand.....
Thanks!!
(This post was last modified: 07-09-2014, 06:50 AM by standardtwin.)
One has nothing to do with the other but without proper recapping you stand to incur a multitude of unrelated problems.
As for the can acting as an antenna potentially it can be because the can lost its connection to the chassis which could be restored in various ways. The screw has a capacitive coupling to other things, which can lead to this also. It does not matter, and the screw is best adjusted with a plastic non-magnetic tool.
Do not recommend adjusting the padders in the IF cans or anywhere else if you are just beginning. They are used to align the radio in a very specific order. Although there are "shortcuts" one can use to get an already playing set play even better by judicious adjustment of certain padders, this is best left to those with experience.
Since you are definitely motivated to learn, recommend reading older books about these old sets. Chuck should be able to make you a reprint of the Philco Alignment instructions AND answer specific questions if you decide to order his package for your set. For 7.00 you get superior quality reprints of all pertinent Philco Factory info for your set.
Welcome to the Phorum!! On 1942 sets there is likely to be rubber wiring that will need to be replaced. It will be brittle and fall apart if moved. See this link http://www.philcoradio.com/tech/wiring.htm .
As said, wiring can be a problem. You may want to test continuity of RF/IF Coils, and in fact all transformers so you know what you may be in for. Seems like you do have some spare parts from the junker which may come in handy.
What's interesting to me is the fact that the one chassis has more of the cloth covered wire than rubber in many places. Its not replaced,looks factory to me. I wonder why?
Well I did "adjust" the IF can, as I had thought it was incorrect to have the screw protruding out as far as it was. I got it back relatively where it was.
Which would you do, transfer the good transfer and output Xformer to the chassis where it had burned, or transfer the tuning pot, dial and such to the one pictured?. The burned chassis has an excellent tuner and glass assy.
Chuck did my BOL tone arm for my 41-608, so will reach out for the diagram....
"It depends." Just about any chassis can be made to work again. I'd put my nickel on the burnt one, as probably no further tinkering was done to it, and if that's the one with cloth covered wires, that would clinch it.
Take lots of pictures before surgery.
Took your advice. I performed surgery on the parts chassis, and moved the transformer and AC block to the burned chassis. The burned chassis was the one in the cabinet, and I think one of the electroytics went, and took it out, it literally looks like it was on fire. I was a little hesistant, and then figured if I screw it up, I'll just fix it. Good thing I own magnifier glasses, I just can't see how to solder the joints right without them.
I bought the correct electrolytics, and installed them. I had to replace a rubber wire from the one electrolytic to the other side of the chassis. As this set was clearly undisturbed, there are more cloth wires than rubber in this set. The other chassis had period fixes in it with crumbling wire....good move not to use that chassis.....
I made a good investment and bought a used old fashioned Variac. The tubes appeared to be OK, as they worked on the parts set. I slowly powered the set up, carefully watching and leaving it at low voltage for a while, then slowly got up to speed. I have crackling out of the speaker, and response to volume but no stations yet. I can tell the volume pot is filthy and is not making good contact inside. I have all the caps coming in the mail, and am going to replace them all. Perhaps when that's done, and I clean the volume switch, I might recieve something.....I hope so, as so far I seem to be on the right track.....
It is recommended you also replace the paper caps, both tubular and the ones in that backelte block. The latter is quite important and has to be a Y rated cap as it seems to be the power line filter.
I went back to it last night, and cleaned the bandswitches and volume pot. Fired it up and Walla!! we have loud and clear reception
Although its tempting to stop, I would imagine that not replacing the paper caps would probably lead to a fatal problem along the way. Now I have the confidence to do it with all of the help recieved.
). I am a newbie, and once had Ron do a 41-608 for me (still going strong..)
