[Eric]

I have an RCA R-32 
http://www.nostalgiaair.org/pagesbymodel...015693.pdf

I suspect my speaker is bad. I get 7K ohms on the Field Leads with them disconnected! Now I'm use to seeing Field Coils 2K ohms or less but I have not worked on one like this so I'm looking for info before I trash it, none of the literature I have says anything about the Field coil resistance. 
Thanks for any help

Eric

[Radioroslyn]

You can find a clue by finding the voltage on each side of the original fc. Note the voltage drop across it. Then do a rough calculation of the hv current that passes thru it. Then you can use ohms law to figure the resistance of the original. There would be a pretty big difference between 2k and 7k.
Or check the plate voltage on the 45's against the known voltage on the chart. If it's high like 50 or 60v w/the 2k fc in place it's probably too low in resistance.

[Eric]

Hey Terry
I have never come across a FC with such a high resistance before (not that I'm that experienced). Usually they seem to fall in the range of 650-2000 ohms but this is such an early set for me.


Input is 110vac resistance across FC is 7K Ohms
So I checked the voltage drop across the FC and I get 222vdc
The individual FC leads are
 302v
 -81v
  221v

the plate voltage from #1 45 is 290vdc
         "         "        "   #2 45 is 302vdc 

so E/R, 222v/7000r=.03a
E/R, 222/.03a=7400 ohms
So it looks like @ 7K the field looks good? Or the bigger question is my math correct!

Thanks
Eric

[OZ4]

Terry    Eric

It depends If all the power goes thru it or if it is a just load on the power supply. 

It's been my limited experience that the field coil does double duty. It serves as a filter choke for the power supply and also as an electro magnet for the speaker.

As a choke filter one would not want 200 volts dropped across it when the power supply is about 400 volts total. That would mean that some 50 percent of the power is lost. 

I would think as a inline (series) choke it should be more like 40 to 60 volts drop max.

If it's a load running at the 400 volts it could be 7k ohms. That's a big load for the power supply at some 57 milliamps.

[OZ4]

The highest voltage on the chart I see is 260 volts so the power supply is likely to be some 300 to 350 volts. 

That would mean the choke voltage should be on the lower end. 

[OZ4]

What I would do is to substitute a resistor until I got the voltages close to the chart voltages. That will tell you what the resistance of the choke should be. 

It will be a healthy size resistor some 10 to 15 watts.  Start with 1k and see what you get.

[OZ4]

If I read the drawing correctly the speaker field coil is a series choke but only for the output tubes.

And on the chart it shows 28MA each so the coil in question should have about 56MA thru it. 

With a 1k resistor that would be 56 volts drop. Sounds a little high. 

[Eric]

After more searching I believe that this is not the original speaker so I'm not sure what the FC resistance should be I am waiting for a reply from another board as he says he has an R-32 and will check the resistance . I have a temporary rig for the Filter caps but need to make that permanent and also work on the voltage divider which has some other resistors spliced in. I also get some very low readings on the grid leak resistors which should be .5meg.

Eric

[Eric]

New information as the saga continues, In my quest for the value of the FC coil it was suggested I send an email to the Radiola Guy and I did and heard back and he says the FC coil should be 1400 ohms. I have also figured out this is not the original speaker among other things that have been done. I think for now I will put in a PM speaker with a 1400 ohm resistor and see if I can get something out of this.

[rghines1]

The Shoeless Joe Jackson Museum in SC is looking for 2 radios to duplicate a picture scene shown on their home page. If you're willing to donate it they would likely accept it as a prop. Curator is looking for a General Electric L-630 and an RCA Victor R-32 They contacted me but have the RCA Victor R-52.

https://www.shoelessjoejackson.org/

Richard

[OZ4]

For what it's worth I measured the voltage of the FC on my 650 chassis. The drawing claims it's  1125 ohms and I measured 76 volts across it.

[Eric]

Yes, I have already donated the restored GE L-630 and he brought the R-32 to me to see if I can get it going and to refinish the Cabinet at a minimum. The Chassis has been messed with and I'm trying to sort out what has been done as so far it now powers up bet only has a hum. So that is where I'm at.
I have the cabinet just about done a few more repairs to the veneer to do.

Eric