Airline Rudolph 05gcb-1540

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Airline Rudolph 05gcb-1540

Post by Rickey on Wed Oct 12, 2011 6:16 am

I have recapped the electrolytics in this radio. At first I had no audio, then I jumpered it to another radios speaker/transformer, then I got a low hum. It has a resistor looking part that I think is a cap. Should I change it out? The tubes are hard to get to to check voltages. The transformer did show like 1.875k on the input and almost zero on the output, tested still in radio. Thanks


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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Wed Oct 12, 2011 6:19 am

Here is a better view of the big "resistor"!

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Re: Airline Rudolph 05gcb-1540

Post by Resistance is Futile on Wed Oct 12, 2011 2:45 pm

Thats a resistor 47 ohm 2 watt
http://sparks-radio-shack.forumotion.com/t144-rudolph-airline-05gcb-1540

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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Wed Oct 12, 2011 4:50 pm

Thanks RIF, it's a whopper!

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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Wed Oct 12, 2011 4:52 pm

I put another transformer on it and replaced all the other caps. I think the one that got the audio tranny was the mica mold! It's singing like a bird now! I mean a reindeer!
Thanks, I truly love the forum!

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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Wed Oct 12, 2011 4:53 pm

Here it is recapped

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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Wed Oct 12, 2011 4:54 pm

Here are the bad guys!

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Re: Airline Rudolph 05gcb-1540

Post by Bill Cahill on Wed Oct 12, 2011 6:21 pm

Congradulations on a job well done!
You need to replace all bad caps before you even attempt to fire up a radio. Alot of radios also used rubber wiring, which is also often bad. Another reason to restore before plugging in.

I doubt the mica mold cap took the transformer, though.
Alot of the cheaper transformers tended to go bad on their own.
Bill Cahill

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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Thu Oct 13, 2011 7:38 pm

Thanks Bill, more to follow!
Shocked

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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Thu Oct 20, 2011 2:50 pm

After a couple of days I get distortion on this set.Now i have some voltages. The cathode on the 50c5 reads 5 volts dc. The cathode resistor reads 190, a little out of the 20 percent range, should be 150. I get low positive voltage on the grid pin ,1.2 volts. I should be on dc, correct? The radio improves vastly when i check the voltage on the cathode!
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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Thu Oct 20, 2011 2:54 pm

the resistors are beyond 20 percent in a couple of cases(30) percent.
Resistor 3 should be a 10 meg and it reads 17 meg! its on the 12at6 on pins 1 and 2, grid and cathode. I ordered a few resistors from mouser, but i dont think i ordered the 10 meg.Would this resistor cause distortion?
Thanks,Rickey

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Re: Airline Rudolph 05gcb-1540

Post by Bill Cahill on Thu Oct 20, 2011 4:18 pm

I don't know what you mean by distortion, but, it would cause issues with sensitivity.
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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Thu Oct 20, 2011 4:45 pm

The radio sounds like a bad filter capacitor, but they are ok!
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Re: Airline Rudolph 05gcb-1540

Post by Bill Cahill on Thu Oct 20, 2011 5:11 pm

Also, on pin 2 of 50C5 you should get low negative, or 0 volts. That's usually a bad coupling cap from plate of pre amp to 50C5. Replacement is mandetory.
Don't leave any original paper caps in it.
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Re: Airline Rudolph 05gcb-1540

Post by Rickey on Fri Oct 21, 2011 11:46 am

All caps were changed to begin with. I get very low positive volts on pin 2. The audio tube gets hotter than a 2 dollar pistol! The dial light glows very dim also?
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