(02-08-2017, 08:54 PM)keith49vj3 Wrote: Just to be sure, you're getting 1100 ohms when you test your field coil by putting your ohmmeter across the positive terminals of the two 8uf caps?
Keith
If you can get ac hum from touching the cap of the 75 then the choke is conducting. If not there wouldn't be any HV throughout the chassis except for at the filament of the 80.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
(This post was last modified: 02-08-2017, 09:41 PM by Radioroslyn.)
Terry, the reason I asked that question is that it would be easy to hook the field coil between the 8 and 16uf cap rather than between the 8uf caps. I have no idea if you would get hum that way. On two of my 610's these caps were in different positions than shown in the manual (and these were unrestored originals). I restuffed them one at a time, put them into the radio and was really confused when tracing the wiring. Here's the cap placement that was on two of my radios (I need to check the third). Parts 54 and 41 were reversed.
If I remember correctly, the 610 had several numbering wrrors on the schematic, including the electrolytics. There was a description of them in the documentation on nostalgiaair.
There are several errors in the schematic and diagram. I am restarting my 610 restoration. I have documented the errors I found on the one I am restoring. I'll bump my thread so you can take a look, as I start up.
If I could find the place called "Somewhere", I could find "Anything"
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44
Well, I must have done something wrong the first and second time checking the field coil. It was ohming at a little over 1100 and now it is showing at the number below.
It's hard to tell without labels on your photo. Are the speaker leads that go to the field coil white? Is that a 100ohm resistor going between the positive of the 8uf cap and the positive of the 16uf cap?
Keith
If the circled resistor is a 10K you've got the value right but it needs to be a 3W resistor. Since mine is on my bench I can take resistance readings from each tube pin to ground and we can compare mine to the readings you get.
Radiohound, I'm not very good at troubleshooting but these are the resistance readings I get for all of the tubes on my 610. These were all measured to chassis ground. If I made a mistake someone will probably let me know. The radio does play well so that's a good sign. I don't think Philco published tube pin resistance readings for this radio.
Keith
80 tube
Pin1 85K
Pin2 393 ohms
Pin3 402 ohms
Pin4 85K
Yes it is a 10k resistor and the speaker wires are white. Probably not to standards. I did miss the fact that I should have a 3 watt here though. Also I just learned how to put pictures on here and I will try to find out how to label them too. If you have info on how to do that I am absorbing everything you guys send. By the way, I work 3rd shift 4 days on and 3 days off. My days on are 14 to 18 hours long so if I don't answer right away, that is why. I will do resistance readings and post them Saturday evening. I understand that this with the speaker unplugged, right?
(02-13-2017, 09:13 PM)keith49vj3 Wrote: It's hard to tell without labels on your photo. Are the speaker leads that go to the field coil white? Is that a 100ohm resistor going between the positive of the 8uf cap and the positive of the 16uf cap?
Keith
Radiohound, disconnect one of the wires that connect to the field coil on you speaker and see if you still get the 5.15 ohm resistance reading. Using wires that are all the same color would make it easy to make a mistake when rewiring. I consider my self an advance beginner and hopefully some of the experts on this forum will jump in. If you measured the field coil at 1100 ohms before and now it's 5.15ohm I'm thinking you connected the wires in the chassis incorrectly.
Keith
Morzh, You are correct. I was using a tablet and didn't see the K. Am I giving bad advice? I'm still thinking measuring the field coil with a lead disconnected could rule out a wiring problem in the chassis.
Keith
No bad advice; any measurement is a good measurement.
This said, if you have a resistance (the coil in this case) that gives you 5k, then if you disconnect things it will not get any smaller. Only larger. The initial resistance was 1.1k and then became 5k, so if you disconnect things they won't get it back to 1.1K.
It is still interesting how in the world this could happen. It is rare if at all possible that a coil (not a resistor but an actual wound coil) could develop not an open, not a few order of magnitude higher resistance, but a finite number just a few times large than the original. Theoretically....the soldering joint of the lead wire to the magnet wire getting really bad but still conducting or carbonized......never saw that though.
Good sign is, if it is the case, it is repairable without having to rewind the coil, just open the paper and inspect the wire. Unless it is the inner wire and is not accessible. But let's hope for the best.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Morzh, I see your point, I thought it was a good idea before you pointed out the "K". But the field coil could be completely open and the 5.5K ohms could be resistance within the chassis, correct?
Keith
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