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 Post subject: Westinghouse (RCA R-5AC) restoration questions
PostPosted: Jun Tue 18, 2019 11:49 pm 
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Joined: Mar Thu 03, 2011 8:53 pm
Posts: 1039
Location: Davis, CA
This radio has a Westinghouse logo on it but it was made by RCA. Circuit diagram is here. http://www.nostalgiaair.org/pagesbymode ... 040311.pdf

All the resistors in this radio are on a "resistor board". Here is a picture of the board.

All the resistors in the radio are on this board and appear to be 1 watt in size except for the one on the left which looks like it is 2 watts. The 2 watt resistor is R4. Do these resistors need to have this wattage?

Thanks, Bob


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Westinghouse-RCA R-5AC resistor board (2) - resize.jpg
Westinghouse-RCA R-5AC resistor board (2) - resize.jpg [ 369.01 KiB | Viewed 214 times ]
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 Post subject: Re: Westinghouse (RCA R-5AC) restoration questions
PostPosted: Jun Wed 19, 2019 1:46 am 
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Joined: Nov Tue 14, 2017 5:09 am
Posts: 1634
Location: Austin, Texas
It appears that you have all the information to calculate the resistor wattages.
For instance R2 is 600 ohms and the voltage chart shows 3 volts on the cathode of the tube 1.
The power would be (3 x 3) / 600 = 0.015 watts
R4 is about 1 watt but the others appear to be much less than a watt.

Jay


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 Post subject: Re: Westinghouse (RCA R-5AC) restoration questions
PostPosted: Jun Wed 19, 2019 6:59 pm 
Member

Joined: Mar Thu 03, 2011 8:53 pm
Posts: 1039
Location: Davis, CA
Thanks Jay for pointing out the voltages. I think I've got all of the resistors figured out except for R10 and R11. What is the voltage drop across these two?

Thanks, Bob


Last edited by rck46 on Jun Wed 19, 2019 8:52 pm, edited 1 time in total.

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 Post subject: Re: Westinghouse (RCA R-5AC) restoration questions
PostPosted: Jun Wed 19, 2019 8:50 pm 
Member

Joined: Mar Thu 03, 2011 8:53 pm
Posts: 1039
Location: Davis, CA
Another question. I have checked out continuities of all the coils. I find that L3 shows 8 ohms while the circuit diagram indicates it should be 91 ohms although my copy is hard to read. Could it possibly be 9.1 ohms or is the coil shorted and needs to be rewound?

Thanks, Bob


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 Post subject: Re: Westinghouse (RCA R-5AC) restoration questions
PostPosted: Jul Tue 16, 2019 12:03 am 
Member

Joined: Mar Thu 03, 2011 8:53 pm
Posts: 1039
Location: Davis, CA
I went through this radio and replaced all the caps and resistors. I replaced C18, the 2 mfd paper cap with a 4.7mfd, 450 volt electrolytic.

I get some reception at the lower end of the dial but nothing at the upper end of the dial unless I touch the grid cap of tube 1. When I do this I get no reception at the lower end of the dial.

I get a good response across the dial when inputing a signal at the antenna lead from my signal generator.

I tried adusting the two trimmers, C3 and C10, at 1400kc but did not improve results.

B+ measures about 230v.

Could the problem lie with L-3 which measures about 8 ohms rather than 91 ohms as shown on the circuit diagram? All other coils ohm out ok.

All tubes test good.

Any suggestions will be appreciated.

Thanks, Bob


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 Post subject: Re: Westinghouse (RCA R-5AC) restoration questions
PostPosted: Jul Sun 21, 2019 10:39 pm 
Member

Joined: Mar Thu 03, 2011 8:53 pm
Posts: 1039
Location: Davis, CA
I am bumping this up with the hope that someone has some ideas on my reception problem. I pulled L3 from the radio. It is on the same coil form as L4, L5, and L6. It is the light colored coil in the following photo. On close inspection I do not see any problems with it. As I mentioned earlier it measures about 8 ohms rather than the 91 ohms indicated on the circuit diagram. The yellow cap you see is C-13.

Bob


Attachments:
Westinghouse (RCA R-5 AC) coils L3, 4, 5, 6 (2),resize.jpg
Westinghouse (RCA R-5 AC) coils L3, 4, 5, 6 (2),resize.jpg [ 343.81 KiB | Viewed 25 times ]
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