10-17-2022, 03:51 PM
MrFixr55,
In response to your questions, adjusting the rear tuning capacitors, C7 and C11, initially did the most to improve the volume control. In fact, I ended up having to tighten C11 almost as far down as it would go. C5 also seemed to greatly improve the volume levels as well, but mostly in the upper bands. I actually went through the alignment procedures twice trying to maximize the signal and volume output.
When working on this set, I removed C5, C11, C13, and C17 in order to clean the mica wafers as best as I could. That's probably why adjusting C7 and C11 resulted in the best improvement as I completely loosened the nuts to get under the mica. Didn't have to adjust C13 or C17 much at all.
The volume output still increases when I hover over the 77 tube or touch the cap, but not nearly as much of a difference as their was before the alignment. At least now I don't have to turn the volume control almost to maximum to get anything audible through the speaker except for some of the more distant stations.
For the alignment, I used a small AM transmitter to broadcast a 1 kHz test signal at 600 kHz on the dial which I calibrated using my Kenwood stereo that displays the frequency on a digital readout. Not perfect, but the set seems to pick up stations close to their locations on the dial. I probably pick up 4 stations with only a 3ft antenna.
I want to thank you and others on this site. This forum has been a great well of knowledge. This is only my third radio, so I've got lots to still learn. A Philco 41-608 was my first set, and it didn't give me any problems after replacing the caps, resistors, and some of the wiring. Still have the Beam of Light tonearm to tackle, but the radio portion works great. The 84b looked like it would be a lot simpler to fix, but that turned out be more work...but more rewarding too.
And thanks for the compliment on the rewiring. So much of the wiring was already deteriorating that it was simpler to just tackle it all at once instead of having to go back and fix something else down the road. Besides, it's been very helpful in learning to read the schematics and understanding the operation of the radios.
Jim
In response to your questions, adjusting the rear tuning capacitors, C7 and C11, initially did the most to improve the volume control. In fact, I ended up having to tighten C11 almost as far down as it would go. C5 also seemed to greatly improve the volume levels as well, but mostly in the upper bands. I actually went through the alignment procedures twice trying to maximize the signal and volume output.
When working on this set, I removed C5, C11, C13, and C17 in order to clean the mica wafers as best as I could. That's probably why adjusting C7 and C11 resulted in the best improvement as I completely loosened the nuts to get under the mica. Didn't have to adjust C13 or C17 much at all.
The volume output still increases when I hover over the 77 tube or touch the cap, but not nearly as much of a difference as their was before the alignment. At least now I don't have to turn the volume control almost to maximum to get anything audible through the speaker except for some of the more distant stations.
For the alignment, I used a small AM transmitter to broadcast a 1 kHz test signal at 600 kHz on the dial which I calibrated using my Kenwood stereo that displays the frequency on a digital readout. Not perfect, but the set seems to pick up stations close to their locations on the dial. I probably pick up 4 stations with only a 3ft antenna.
I want to thank you and others on this site. This forum has been a great well of knowledge. This is only my third radio, so I've got lots to still learn. A Philco 41-608 was my first set, and it didn't give me any problems after replacing the caps, resistors, and some of the wiring. Still have the Beam of Light tonearm to tackle, but the radio portion works great. The 84b looked like it would be a lot simpler to fix, but that turned out be more work...but more rewarding too.
And thanks for the compliment on the rewiring. So much of the wiring was already deteriorating that it was simpler to just tackle it all at once instead of having to go back and fix something else down the road. Besides, it's been very helpful in learning to read the schematics and understanding the operation of the radios.
Jim
