Yesterday, 11:28 PM
Phorum Phriends,
I have some questions about resistors in my 42-345.
Before getting to the confessional aspect of my post, I'd like to say first that I have fixed up my 42-365, which I call big Phil. I replaced the electrolytic capacitors and another paper capacitor that looked like it had a pustule. I installed a new power cord and replaced some of the rubber wiring. I fixed the dial cord. I also added green LED lights to replace the original dial lights. The radio sounds great and looks great, too. I love it.
Alas, I got a little cocky with my 42-345, which I call Little Phil. I deviated from my rule of doing just one thing at a time to see whether the radio worked afterwards. This sloppiness led me to rush, and I replaced an electrolytic capacitor with the polarity reversed. In the attached schematic, the capacitor is number 57, which connects between 7Y4 and 7B5.
I may have made other errors; I cannot tell yet.
What happens if you put the capacitor in the wrong way? At first, nothing. The radio played and played beautifully for about five minutes. My employee and I enjoyed it. He left for the day. I listened a bit longer, and then the sound stopped. I went over to look at the radio, and 7Y4 was glowing brightly red. I smelled a little something. I unplugged the radio. I look later the capacitor, which did not blow up, but looked a little scorched at one end.
My questions for the Phorum are easy. My questions are about the value of the various resistors.
In the first photo, there is a big resistor in the back with two red rings, one brown, and then silver, I think. This is 33-122436, a 220 Ohm resistor. Correct?
Beneath the double red band is a blue, grey, black, silver resistor. This is 33-068136, 68 Ohms. Correct?
Are they both ½ watt? 436 and 136 mean something, but I forget what.
Next, brown, black, green. Am I right this is 33-510339 and 1 Megaohm?
Last, there's a red, red, followed by, I think, yellow? if so, that's 220,000 ohms and 33-422339. Right?
My brother, who actually knows something about electronics, assures me that the resistors were not the cause of the smoke that I saw when I plugged Little Phil in. Take a look at the 220 Ohm sausage, and you'll see a crack where the smoke came out. Same with the 68 ohm, which appears scorched.
First, I'd like to know if I have the parts right, because I will replace them.
Second, I guess I would like to know if the damage is consistent with the mistake that I think I made. (Another hypothesis would be that I did something wrong with the other capacitors I replaced or maybe I created some kind of short.)
Feel free to guide me regarding my plan. Keep in mind that while I can solder and am not stupid, I'm not very knowledgeable about electronics. I also only have a multimeter, nothing fancier.
My plan is to
1. confirm the polarity of the 12 uf capacitor and put it in the right was the next time.
2. I am also confirming that I soldered everything to the right pins. I have a vague worry that I'm on the wrong pin.
3. I am going to replace the burned up 220 and 68 ohm resistors along with, I think, the others about which I asked.
4. I am going to put a new 7Y4 tube in. I may not have wrecked that one, but I don't know how to test it, so I bought a new one.
5. I'm also rechecking the wires to see that I did not melt anything.
After doing this, I hope to have Little Phil back in action. What say ye?
Thank you,
Tom Russell
Denver, CO
I have some questions about resistors in my 42-345.
Before getting to the confessional aspect of my post, I'd like to say first that I have fixed up my 42-365, which I call big Phil. I replaced the electrolytic capacitors and another paper capacitor that looked like it had a pustule. I installed a new power cord and replaced some of the rubber wiring. I fixed the dial cord. I also added green LED lights to replace the original dial lights. The radio sounds great and looks great, too. I love it.
Alas, I got a little cocky with my 42-345, which I call Little Phil. I deviated from my rule of doing just one thing at a time to see whether the radio worked afterwards. This sloppiness led me to rush, and I replaced an electrolytic capacitor with the polarity reversed. In the attached schematic, the capacitor is number 57, which connects between 7Y4 and 7B5.
I may have made other errors; I cannot tell yet.
What happens if you put the capacitor in the wrong way? At first, nothing. The radio played and played beautifully for about five minutes. My employee and I enjoyed it. He left for the day. I listened a bit longer, and then the sound stopped. I went over to look at the radio, and 7Y4 was glowing brightly red. I smelled a little something. I unplugged the radio. I look later the capacitor, which did not blow up, but looked a little scorched at one end.
My questions for the Phorum are easy. My questions are about the value of the various resistors.
In the first photo, there is a big resistor in the back with two red rings, one brown, and then silver, I think. This is 33-122436, a 220 Ohm resistor. Correct?
Beneath the double red band is a blue, grey, black, silver resistor. This is 33-068136, 68 Ohms. Correct?
Are they both ½ watt? 436 and 136 mean something, but I forget what.
Next, brown, black, green. Am I right this is 33-510339 and 1 Megaohm?
Last, there's a red, red, followed by, I think, yellow? if so, that's 220,000 ohms and 33-422339. Right?
My brother, who actually knows something about electronics, assures me that the resistors were not the cause of the smoke that I saw when I plugged Little Phil in. Take a look at the 220 Ohm sausage, and you'll see a crack where the smoke came out. Same with the 68 ohm, which appears scorched.
First, I'd like to know if I have the parts right, because I will replace them.
Second, I guess I would like to know if the damage is consistent with the mistake that I think I made. (Another hypothesis would be that I did something wrong with the other capacitors I replaced or maybe I created some kind of short.)
Feel free to guide me regarding my plan. Keep in mind that while I can solder and am not stupid, I'm not very knowledgeable about electronics. I also only have a multimeter, nothing fancier.
My plan is to
1. confirm the polarity of the 12 uf capacitor and put it in the right was the next time.
2. I am also confirming that I soldered everything to the right pins. I have a vague worry that I'm on the wrong pin.
3. I am going to replace the burned up 220 and 68 ohm resistors along with, I think, the others about which I asked.
4. I am going to put a new 7Y4 tube in. I may not have wrecked that one, but I don't know how to test it, so I bought a new one.
5. I'm also rechecking the wires to see that I did not melt anything.
After doing this, I hope to have Little Phil back in action. What say ye?
Thank you,
Tom Russell
Denver, CO
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