02-10-2021, 11:20 PM
Thanks all.
I finally got around to checking out the dial pilot lamp issue. I took the chassis out of the case (again) and removed a couple of tubes to check resistors. The R29 candohm (sp?) checked out per schematic for 53 ohms parallel to the lamp and 175 ohms to the rectifier tube. So, I replaced the lamp (#47 is correct), turned the set on, and waited to see what would happen.
This time, the lamp started bright, dimmed as the filaments warmed up, came back to normal brightness as sound began coming from the speaker and stayed on as it should.
Then, I put the chassis back in the cabinet, turned it on, normal up till sound from the speaker and the lamp flashed out again.
Head scratching time...
Trying the same thing over and over again and expecting different results is the definition of insanity, right?
Now, I don't know if the following makes any sense or not. I am getting really good at taking the chassis out and putting it back in. This all started after I got this little radio working and put it all back in the case and the dial string broke!
There are three screws that hold the chassis to the cabinet. One in the front center and two on the rear about an inch in from either side of the radio. Two of these screws appear to be copper plated originals. One is a newer shiny hot dipped self-tapping screw like one might use for sheet metal. It fits and tightens up perfectly, and it is maybe a couple of mm's longer than the original two.
I have found that if I don't use the longer screw in the front center, and if I use either of the other screws, I can only tighten that center screw to just contact the case, then the lamp will not flash-pop!
I think the metal can resistor may be affected by a slight warping of the front of the chassis, where it is mounted, when the long screw is used or the short ones are over-tightened, and that may be the cause of the lamp burn out. Could it be this touchy?
Anyway. I am thinking about bypassing the metal resistor with a couple of ceramics (I think I can find a 5w 57 ohm and a 10w 175 ohm) just to see if the problem goes away. I haven't been able to think of a way to "warp" the chassis and measure the resistance at the same time yet.
For now, the radio is back together playing fine. I have been listening to long distance stations tonight. The dial lamp is working just fine also. I have turned it on and off a couple of times just to see how it goes and everything seems fine for now.
-Dave
p.s. The furnace is fine now, too.
I finally got around to checking out the dial pilot lamp issue. I took the chassis out of the case (again) and removed a couple of tubes to check resistors. The R29 candohm (sp?) checked out per schematic for 53 ohms parallel to the lamp and 175 ohms to the rectifier tube. So, I replaced the lamp (#47 is correct), turned the set on, and waited to see what would happen.
This time, the lamp started bright, dimmed as the filaments warmed up, came back to normal brightness as sound began coming from the speaker and stayed on as it should.
Then, I put the chassis back in the cabinet, turned it on, normal up till sound from the speaker and the lamp flashed out again.
Head scratching time...
Trying the same thing over and over again and expecting different results is the definition of insanity, right?
Now, I don't know if the following makes any sense or not. I am getting really good at taking the chassis out and putting it back in. This all started after I got this little radio working and put it all back in the case and the dial string broke!
There are three screws that hold the chassis to the cabinet. One in the front center and two on the rear about an inch in from either side of the radio. Two of these screws appear to be copper plated originals. One is a newer shiny hot dipped self-tapping screw like one might use for sheet metal. It fits and tightens up perfectly, and it is maybe a couple of mm's longer than the original two.
I have found that if I don't use the longer screw in the front center, and if I use either of the other screws, I can only tighten that center screw to just contact the case, then the lamp will not flash-pop!
I think the metal can resistor may be affected by a slight warping of the front of the chassis, where it is mounted, when the long screw is used or the short ones are over-tightened, and that may be the cause of the lamp burn out. Could it be this touchy?
Anyway. I am thinking about bypassing the metal resistor with a couple of ceramics (I think I can find a 5w 57 ohm and a 10w 175 ohm) just to see if the problem goes away. I haven't been able to think of a way to "warp" the chassis and measure the resistance at the same time yet.
For now, the radio is back together playing fine. I have been listening to long distance stations tonight. The dial lamp is working just fine also. I have turned it on and off a couple of times just to see how it goes and everything seems fine for now.
-Dave
p.s. The furnace is fine now, too.
