Home  Resources  References  Tubes  Forums  Links  Support 
51 Lincoln Radio,plays better now-but still weak!!
4/27/2001 9:47:18 PMDennis Lavin
Thanks guys(Denis & John) I found a bad screen droping resistor way out of specs! It's supposed to be 12K ohm and was actualy @ 23K ohm's. Replaced it and now the screenvoltage is correct and plate volts correct, But still seems weak reception. Rechecked the caps and re-aligned set.I am doing this with the antenna inside the shop, mabe in the car will give better results or am I missing somthing still??
4/29/2001 11:05:26 AMJohn McPherson
Hi,

Good to hear there is improvement. Chances are good that the radio should have the IF's peaked. Most production radios of that time really suffered in performance due to a lack of tuning the radio after it was assembled. The radio also needs to have a good ground plane for the antenna. Check that there is continuity between the grounding base of the antenna mount, and the engine ground. Be careful not to tighten the base too tight to the fender, as you may deform the fender by over-tightening the base mount.

Best location to tune up and trim the RF section is in the car attached to the antenna you are going to use. You can tune it to some extent on the bench, and get good performance too, but when it is in the car, it is attached to the antenna system that it will be using.

If you have the permeability tuned reciever (I forget what style that one used), you can tune the slugs for optimum performance. It gets time consuming, but the basic tuning principle is the same as that of capacitance tuning.

However, even at 50 years of age, unless something degraded severely on the frame that the slug threads though, or it got bent, or was never tuned very well in the begining, you may not need to do much more than simply peak the IF's for maximum signal at a single peak, and trim the antenna cap.

If all of that has ben done, and the signal remains weak, swap the second detector (most likely a 6SQ7) for another one that reads good, and if that does not correct it, try the first RF and IF stages for the same thing.

: Thanks guys(Denis & John) I found a bad screen droping resistor way out of specs! It's supposed to be 12K ohm and was actualy @ 23K ohm's. Replaced it and now the screenvoltage is correct and plate volts correct, But still seems weak reception. Rechecked the caps and re-aligned set.I am doing this with the antenna inside the shop, mabe in the car will give better results or am I missing somthing still??

4/29/2001 12:34:51 PMDennis Lavin
: Hi,

: Good to hear there is improvement. Chances are good that the radio should have the IF's peaked. Most production radios of that time really suffered in performance due to a lack of tuning the radio after it was assembled. The radio also needs to have a good ground plane for the antenna. Check that there is continuity between the grounding base of the antenna mount, and the engine ground. Be careful not to tighten the base too tight to the fender, as you may deform the fender by over-tightening the base mount.

: Best location to tune up and trim the RF section is in the car attached to the antenna you are going to use. You can tune it to some extent on the bench, and get good performance too, but when it is in the car, it is attached to the antenna system that it will be using.

: If you have the permeability tuned reciever (I forget what style that one used), you can tune the slugs for optimum performance. It gets time consuming, but the basic tuning principle is the same as that of capacitance tuning.

: However, even at 50 years of age, unless something degraded severely on the frame that the slug threads though, or it got bent, or was never tuned very well in the begining, you may not need to do much more than simply peak the IF's for maximum signal at a single peak, and trim the antenna cap.
:
: If all of that has ben done, and the signal remains weak, swap the second detector (most likely a 6SQ7) for another one that reads good, and if that does not correct it, try the first RF and IF stages for the same thing.


: : Thanks guys(Denis & John) I found a bad screen droping resistor way out of specs! It's supposed to be 12K ohm and was actualy @ 23K ohm's. Replaced it and now the screenvoltage is correct and plate volts correct, But still seems weak reception. Rechecked the caps and re-aligned set.I am doing this with the antenna inside the shop, mabe in the car will give better results or am I missing somthing still??

OK, I will put it in the car and see what happens, Thanks again, Dennis.

5/2/2001 11:06:34 PMDenis Niehues
Do not use too long a coax cable for a car radio. Those old things
got REAL picky about the capacitance buildup in long cables. Use a regular
car radio antenna and not over 4 or 5 feet of cable. Be sure to tweek
the antenna matching cap when installation is complete. Find a blank spot
on the dial around 1400 1500kc and trim for loudest noise. Denis: : Hi,

: : Good to hear there is improvement. Chances are good that the radio should have the IF's peaked. Most production radios of that time really suffered in performance due to a lack of tuning the radio after it was assembled. The radio also needs to have a good ground plane for the antenna. Check that there is continuity between the grounding base of the antenna mount, and the engine ground. Be careful not to tighten the base too tight to the fender, as you may deform the fender by over-tightening the base mount.

: : Best location to tune up and trim the RF section is in the car attached to the antenna you are going to use. You can tune it to some extent on the bench, and get good performance too, but when it is in the car, it is attached to the antenna system that it will be using.

: : If you have the permeability tuned reciever (I forget what style that one used), you can tune the slugs for optimum performance. It gets time consuming, but the basic tuning principle is the same as that of capacitance tuning.

: : However, even at 50 years of age, unless something degraded severely on the frame that the slug threads though, or it got bent, or was never tuned very well in the begining, you may not need to do much more than simply peak the IF's for maximum signal at a single peak, and trim the antenna cap.
: :
: : If all of that has ben done, and the signal remains weak, swap the second detector (most likely a 6SQ7) for another one that reads good, and if that does not correct it, try the first RF and IF stages for the same thing.

:
: : : Thanks guys(Denis & John) I found a bad screen droping resistor way out of specs! It's supposed to be 12K ohm and was actualy @ 23K ohm's. Replaced it and now the screenvoltage is correct and plate volts correct, But still seems weak reception. Rechecked the caps and re-aligned set.I am doing this with the antenna inside the shop, mabe in the car will give better results or am I missing somthing still??

: OK, I will put it in the car and see what happens, Thanks again, Dennis.

5/10/2001 10:56:31 PMDennis Lavin
Just replaced ALL of the cap's and it seems to sound better! We are installing it in the car this week end, so I will see if it works Ok in the car. Thank's guys for your help again, will let you know the results, Dennis L. : Do not use too long a coax cable for a car radio. Those old things
: got REAL picky about the capacitance buildup in long cables. Use a regular
: car radio antenna and not over 4 or 5 feet of cable. Be sure to tweek
: the antenna matching cap when installation is complete. Find a blank spot
: on the dial around 1400 1500kc and trim for loudest noise. Denis: : Hi,

: : : Good to hear there is improvement. Chances are good that the radio should have the IF's peaked. Most production radios of that time really suffered in performance due to a lack of tuning the radio after it was assembled. The radio also needs to have a good ground plane for the antenna. Check that there is continuity between the grounding base of the antenna mount, and the engine ground. Be careful not to tighten the base too tight to the fender, as you may deform the fender by over-tightening the base mount.

: : : Best location to tune up and trim the RF section is in the car attached to the antenna you are going to use. You can tune it to some extent on the bench, and get good performance too, but when it is in the car, it is attached to the antenna system that it will be using.

: : : If you have the permeability tuned reciever (I forget what style that one used), you can tune the slugs for optimum performance. It gets time consuming, but the basic tuning principle is the same as that of capacitance tuning.

: : : However, even at 50 years of age, unless something degraded severely on the frame that the slug threads though, or it got bent, or was never tuned very well in the begining, you may not need to do much more than simply peak the IF's for maximum signal at a single peak, and trim the antenna cap.
: : :
: : : If all of that has ben done, and the signal remains weak, swap the second detector (most likely a 6SQ7) for another one that reads good, and if that does not correct it, try the first RF and IF stages for the same thing.

: :
: : : : Thanks guys(Denis & John) I found a bad screen droping resistor way out of specs! It's supposed to be 12K ohm and was actualy @ 23K ohm's. Replaced it and now the screenvoltage is correct and plate volts correct, But still seems weak reception. Rechecked the caps and re-aligned set.I am doing this with the antenna inside the shop, mabe in the car will give better results or am I missing somthing still??

: : OK, I will put it in the car and see what happens, Thanks again, Dennis.



© 1989-2025, Nostalgia Air