Hi Everyone,
I recently picked up a non working Pioneer SX-770 receiver. After a full rebuild of the amp board + general recapping the amp works well and sounds fine.
Concerning the FM tuner, it was catching zero signal , so after a clean/lubrication of the tuner gang contacts & some basic alignment, it now picks up all stations really well, with a strong signal & with stereo/muring working fine.
The issue is the frequency on the dial doesn't correspond to the station, so it reads about 1.5MHz too low on the dial. I adjusted the LO screw as much as I could but this only has relatively minor impact.
Normally I would just adjust the TCO (Tuning cap oscillator) a bit to better align the dial, but in my case it justs turns endlessely with no impact whatsoever on the sound or station. I figure the cap is broken.
The FM front end has a kind of soldered shielding that I cant take apart. Also I don't want to fiddle with the pointer on the string.
Is there anyway of adding an external adjuster perfroming an equivalent function as the TCO cap ? Not sure how it works not what it is (adjustable capacitor ?)
Or maybe I will need to take the shielding off, but will need a powerful soldering iron for that, and try to fit a new TCO cap if these things are avialable.
Would appreciate any advice.
I recently picked up a non working Pioneer SX-770 receiver. After a full rebuild of the amp board + general recapping the amp works well and sounds fine.
Concerning the FM tuner, it was catching zero signal , so after a clean/lubrication of the tuner gang contacts & some basic alignment, it now picks up all stations really well, with a strong signal & with stereo/muring working fine.
The issue is the frequency on the dial doesn't correspond to the station, so it reads about 1.5MHz too low on the dial. I adjusted the LO screw as much as I could but this only has relatively minor impact.
Normally I would just adjust the TCO (Tuning cap oscillator) a bit to better align the dial, but in my case it justs turns endlessely with no impact whatsoever on the sound or station. I figure the cap is broken.
The FM front end has a kind of soldered shielding that I cant take apart. Also I don't want to fiddle with the pointer on the string.
Is there anyway of adding an external adjuster perfroming an equivalent function as the TCO cap ? Not sure how it works not what it is (adjustable capacitor ?)
Or maybe I will need to take the shielding off, but will need a powerful soldering iron for that, and try to fit a new TCO cap if these things are avialable.
Would appreciate any advice.
