04-29-2022, 07:32 PM
If it's wound backward, it will not oscillate no matter which wire is where. The fields are not in phase. They have to be for it to oscillate. Things you learn the hard way..
Philco 60 restoration
04-29-2022, 07:32 PM
If it's wound backward, it will not oscillate no matter which wire is where. The fields are not in phase. They have to be for it to oscillate. Things you learn the hard way..
04-29-2022, 11:19 PM
I have confirmed it is not wound backwards. I looked at the pictures I took of the coils before I re wound them, and I made sure the new coil is wound exactly how the old one was. Exact same direction. I even double checked the connections to make sure the right wire is soldered on the right terminal. Everything is correct. I was searching for maybe a bad ground, but no luck there. I read that the rivet grounds on these radios get corroded over time, but mine are all grounding well. I’ve confirmed that the philco is possessed. There is nothing left for me to check….. I guess it’s time to sell it as a fully restored NON working radio
04-30-2022, 08:28 AM
Maybe it's time to look closely at the switch contacts that select the secondary taps on the coil.
04-30-2022, 10:39 AM
I don't think the band switch would cause the problem, in this radio, all contacts are open in the AM position.
Steve M R Radios C M Tubes
04-30-2022, 11:04 AM
Steve, on the schematic they are open, but are they open in the radio(solder splash, stray piece of wire)? Also, the trimmers and tuning condenser can be checked for shorts.
04-30-2022, 12:03 PM
I was closely examining the band switch, and when it’s on AM broadcast, the contacts are open. I checked them to make sure there isn’t something shorting there, but it’s okay. The radio is worth getting working because it’s in excellent shape. It’s been in our family for a long time. Never been stored in a garage or attic or anything like that.
04-30-2022, 02:14 PM
Brandon, a while back you said you could hear a station faintly if you held the antenna. Can you still get the station? Try touching the grid cap of the 6A7. If this brings in a station then the oscillator is working and the antenna circuit isn't.
04-30-2022, 03:59 PM
Rod
I did touch the grid cap of the 6A7, and no improvement unfortunately. I could hear noise from the speaker when I touch the grid cap. But right now I can’t even get a faint station at all. It’s all very strange… Now I am going to try one thing. A while back I replaced all the resistors that have drifted, but I left the others that tested okay. I’m going to replace the others that are testing okay, just to see what happens. They test spot on, so I left them, but maybe one of those is causing the issue. I did read that resistor 14 and 24 I believe can cause problems… I’m very glad Bob Anderson has a video series on YouTube on a model 60, so I’ve been doing everything exactly how he does it. If Bob Anderson is reading this, I thank you so much for the YouTube videos!
04-30-2022, 04:34 PM
HauI out the old shotgun. I was also thinking you can change part #13 110pf cap.
04-30-2022, 09:36 PM
Rod
The 110pf cap was replaced when I re wound the coil. It was the “mica mold” cap. It’s strange because I thought it was a mica cap, but after some reading, I guess these mica mold caps cause problems and should be treated like a paper cap. It’s not a true mica capacitor.
04-30-2022, 11:20 PM
Micamold was the name of a company that made both mica and paper caps. The confusion comes from the fact that the Micamold paper caps were made with a molded plastic case which looks just like a typical molded mica, only larger.
If the Micamold you replaced was 110 pF then it was an actual mica and most likely still good. The problem Micamolds are typically values from .005 uf to 0.1 uF and are plastic molded case paper caps. These are invariably leaky and are as bad or worse than the usual waxed paper ones. Consequently, all Micamold caps have gotten an undeserved bad reputation, but in reality its the paper ones that are suspect while the smaller value true micas are fine.
05-01-2022, 12:51 AM
Mondial
I didn’t know that thank you! Lots of knowledgeable people on this forum
05-01-2022, 09:56 AM
Just took a stab at the mica. I usually leave them alone but have run into only 2 bad micas.
So I don't have any other ideas. I assume you've swapped out the tube. I stopped using tube checkers for the simple reason they don't simulate the real environment, making it a waste of time.
05-01-2022, 02:18 PM
Rod,
Yeah I don’t even own a tube tester for that very reason. I swapped out the tubes with known good tubes. We will get it going eventually. Just have to find the weird issue that’s causing this mess.
05-02-2022, 09:01 PM
So this 32,000 ohm resistor is measuring 17,000 ohms with my new multimeter. And this is the one that goes to the outer winding of the oscillator coil, so I’m hoping this is the problem! New resistor is coming in tomorrow or Wednesday I believe. Goes to show that cheap multimeters will screw everything up! I’m not sure if 17,000 instead of 32,000 will make the radio not play, but it does need replacing! Time to cross my fingers
« Next Oldest | Next Newest »
Users browsing this thread: 4 Guest(s) |
|