[Solved] Raspy receive for some stations on a President Jackson CB.

[doffo]

Hello everyone,

Got a President Jackson that has some kind of a receive issue. Some stations sound very raspy, while some other stations sound ok. It seems that the stronger stations that come in suffer the problem with the raspy receive on the radio. Same thing was kinda happening on my mobile President Grant 858 chassis with the receive audio. Otherwise, the stations all sound ok on my Grant 146 GTL.

This a sign of capacitors on their way out? Letting the radio warm up for awhile to see if the receive seems to clear up better and not have the raspy sounding stations. But so far, it seems that the stronger stations coming in are the ones that are raspy on the receive audio.

I included 2 videos of what I mean.

View attachment President Jackson Bad Audio 1.mp4
View attachment President Jackson Bad Audio 2.mp4

 

[sp5it]

It is famous bad AGC on Jackson.

1. Change R-43 10k to 1k
2. Change R-41 150k to 270k
3. Change R-47 1.50k to 3.9k
4. Remove capacitor C-31.

 

[doffo]

It is famous bad AGC on Jackson.

1. Change R-43 10k to 1k
2. Change R-41 150k to 270k
3. Change R-47 1.50k to 3.9k
4. Remove capacitor C-31.

Aha! I always wondered about that. I will get to working on it and report back to ya. Thanks for the quick reply.

 

[BC Coyote]

Sp5it.... I have a friend who's brand new Lincoln 2+ has that exact same AGC problem. Is it the same board as the Jackson and do the same component changes happen to remedy the problem in the Lincoln 2+ as well ?

 

[AudioShockwav]

Sp5it.... I have a friend who's brand new Lincoln 2+ has that exact same AGC problem. Is it the same board as the Jackson and do the same component changes happen to remedy the problem in the Lincoln 2+ as well ?

The Jackson above is 40+ years old with thru hole construction not related to today's offering.
Uniden was well aware of the problem in the jack and never addressed it at the manufacturing level.

73
Jeff

 

[BC Coyote]

Thanks Jeff ! I kinda figured they would be different beasts. 40 years and they still have that problem..... good grief.
Do you know if there is a fix out there for the Lincoln 2+ AGC problem ? I'm guessing it might be all SMT stuff. Ugh....my hands are a little too old and clumsy for that stuff !

 

[doffo]

It is famous bad AGC on Jackson.

1. Change R-43 10k to 1k
2. Change R-41 150k to 270k
3. Change R-47 1.50k to 3.9k
4. Remove capacitor C-31.

Happy to report that the fix worked wonders. Receive is great once again.

 

[BC Coyote]

Receive is great once again.

Excellent work ! M.R.G.A. "Make Receive Great Again"

 

[sp5it]

Sp5it.... I have a friend who's brand new Lincoln 2+ has that exact same AGC problem. Is it the same board as the Jackson and do the same component changes happen to remedy the problem in the Lincoln 2+ as well ?

Completely different board. Can't help with that.
Mike

 

[Shadetree Mechanic]

Sp5it.... I have a friend who's brand new Lincoln 2+ has that exact same AGC problem. Is it the same board as the Jackson and do the same component changes happen to remedy the problem in the Lincoln 2+ as well ?

I have a Lincoln 2+ with the same problem, I revived an old thread about it.

Improving receive

Is there any way to improve the receive on a President Lincoln 2+ radio?

www.worldwidedx.com

 

[Eldorado828]

Happy to report that the fix worked wonders. Receive is great once again.

@sp5it (Mike) did it again. That's great!

 

[doffo]

Here is the audio after the fix. (Yes, I will fix that stuck needle and light another time. )

View attachment President Jackson Fixed Audio.mp4

 

[AudioShockwav]

Thanks Jeff ! I kinda figured they would be different beasts. 40 years and they still have that problem..... good grief.
Do you know if there is a fix out there for the Lincoln 2+ AGC problem ? I'm guessing it might be all SMT stuff. Ugh....my hands are a little too old and clumsy for that stuff !

Not that I know of, reducing the rf gain helped on the one I had.
There were a couple Lincoln II models , I had one of the first versions that had dismal rx and i returned it. Then a version 2, then the + model that included 12 meters.
a
Almost everything is smt nowadays really need a hot air station if you are old and fat fingered like me......

73
Jeff