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Neutralizing adjustment on Freed Radio NR-78AC
6/25/2000 11:36:14 AMOlaf ,KF4TP
I am fixing up a Freed Radio Model NR-78AC Console Radio.--It has three RF stages,each of which include an adjustable Neutralizing capacitor.--How does one go about adjusting these and at what stage does one start?
Thanks for the help,Olaf,KF4TP.
6/25/2000 12:18:31 PMNorm leal
Hi Olaf

The neutralizing capacitors cancel out the internal capacity of your tube by using an inverted signal.. There will be neutralizing caps for each RF stage in your radio.. You can start with any stage.

First tune in a strong station or use a signal generator. Remove one of the RF tubes and put tape around a filament pin. Insert the tube back into the socket. You should hear the station but weakly. Now adjust the neutralization cap for that stage until the signal is nul. On each side of dead spot you should hear signal..

Do this for the other two stages and your radio will be neutralized using that set of tubes.

Norm


: I am fixing up a Freed Radio Model NR-78AC Console Radio.--It has three RF stages,each of which include an adjustable Neutralizing capacitor.--How does one go about adjusting these and at what stage does one start?
: Thanks for the help,Olaf,KF4TP.

6/25/2000 1:45:30 PMOlaf,KF4TP
: Hi Olaf

: The neutralizing capacitors cancel out the internal capacity of your tube by using an inverted signal.. There will be neutralizing caps for each RF stage in your radio.. You can start with any stage.

: First tune in a strong station or use a signal generator. Remove one of the RF tubes and put tape around a filament pin. Insert the tube back into the socket. You should hear the station but weakly. Now adjust the neutralization cap for that stage until the signal is nul. On each side of dead spot you should hear signal..

: Do this for the other two stages and your radio will be neutralized using that set of tubes.

: Norm

:
: : I am fixing up a Freed Radio Model NR-78AC Console Radio.--It has three RF stages,each of which include an adjustable Neutralizing capacitor.--How does one go about adjusting these and at what stage does one start?
: : Thanks for the help,Olaf,KF4TP.


Thanks,Norm.---It worked like a charm---Whoever thought up the ''Tape method''.Thanks again,you have helped so many times!--Olaf--

6/26/2000 4:50:33 AMManuel Garnelo
Hi, Olaf
If you give me your post address I can send you a couple of photocopies from a vintage book that describe the adjustment procedure (However is exactly what Norm has said).
Manuel


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