12-14-2018, 10:27 AM
Update-- on FM
***the picture shows the radio when the left half of the full FM dial scale as inoperative.****
problem- the FULL left half of the dial scale produced no changes in channels while on FM only.
going from the needle 12 o'clock position ccw to the 9 o'clock, one barely audible channel would dominate this ccw full 90deg sweep.
Item A consists of two dial string pulley's fixed to item B thee "CAM". this pulley / cam system is slipped onto the tuning cap shaft and held in place by two lock screws once it is properly located and coordinated with the dial needle.
Item D is a hinged chunk of flat metal with a round mated cam follower item C that will "follow" the item B "cam" as the tuning cap is rotated.
Item D carries three of item E FM slugs up and down into the FM coils as the tuning cap is rotated.
item F the dial needle and pulley is currently shown approaching the max clockwise position. note the location of item E the FM tuning slugs are still poking up and out of the FM coils. just a tad.
I re-coordinated the tuning cap to tuning cap cam to dial string needle and now the lower half of FM receives properly throughout the 180deg needle swing.
while taking a long hard study of all the working parts, i found one item A lock screw was loose. i also found that the pully item A was dressed too far up on the tuning cap shaft and causing the main "driver" string to be rubbing the chassis.
i know most of you have experience working on slug tuned FM sets but this was my first go and i learned a lot but i still have a long way to go.
***the picture shows the radio when the left half of the full FM dial scale as inoperative.****
problem- the FULL left half of the dial scale produced no changes in channels while on FM only.
going from the needle 12 o'clock position ccw to the 9 o'clock, one barely audible channel would dominate this ccw full 90deg sweep.
Item A consists of two dial string pulley's fixed to item B thee "CAM". this pulley / cam system is slipped onto the tuning cap shaft and held in place by two lock screws once it is properly located and coordinated with the dial needle.
Item D is a hinged chunk of flat metal with a round mated cam follower item C that will "follow" the item B "cam" as the tuning cap is rotated.
Item D carries three of item E FM slugs up and down into the FM coils as the tuning cap is rotated.
item F the dial needle and pulley is currently shown approaching the max clockwise position. note the location of item E the FM tuning slugs are still poking up and out of the FM coils. just a tad.
I re-coordinated the tuning cap to tuning cap cam to dial string needle and now the lower half of FM receives properly throughout the 180deg needle swing.
while taking a long hard study of all the working parts, i found one item A lock screw was loose. i also found that the pully item A was dressed too far up on the tuning cap shaft and causing the main "driver" string to be rubbing the chassis.
i know most of you have experience working on slug tuned FM sets but this was my first go and i learned a lot but i still have a long way to go.