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Zenith 7H920 AM/FM set 7 tube
#42

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.


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Messages In This Thread
Zenith 7H920 AM/FM set 7 tube - by jcassity - 11-30-2018, 03:04 PM
RE: Zenith 7H020 AM/FM set 7 tube - by jcassity - 11-30-2018, 03:11 PM
RE: Zenith 7H020 AM/FM set 7 tube - by jcassity - 11-30-2018, 03:12 PM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 11-30-2018, 07:41 PM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 11-30-2018, 07:51 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-01-2018, 01:01 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-01-2018, 08:55 PM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-01-2018, 09:22 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-02-2018, 10:32 AM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-02-2018, 11:58 AM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-02-2018, 12:31 PM
RE: Zenith 7H920 AM/FM set 7 tube - by KCMike - 12-02-2018, 01:17 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-02-2018, 01:45 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-02-2018, 02:46 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-02-2018, 04:45 PM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-02-2018, 08:24 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-02-2018, 09:00 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-02-2018, 09:02 PM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-02-2018, 10:10 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-03-2018, 11:33 AM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-03-2018, 08:26 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-03-2018, 10:10 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-04-2018, 09:08 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-04-2018, 09:33 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-04-2018, 10:18 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-05-2018, 10:27 AM
RE: Zenith 7H920 AM/FM set 7 tube - by EdHolland - 12-05-2018, 02:30 PM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-05-2018, 05:22 PM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-05-2018, 08:41 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-05-2018, 10:53 PM
RE: Zenith 7H920 AM/FM set 7 tube - by Arran - 12-07-2018, 03:08 AM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-07-2018, 09:29 AM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-07-2018, 02:04 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-07-2018, 10:06 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-08-2018, 09:27 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-09-2018, 11:59 AM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-09-2018, 12:02 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-14-2018, 10:27 AM
RE: Zenith 7H920 AM/FM set 7 tube - by EdHolland - 12-14-2018, 02:41 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-14-2018, 04:27 PM
RE: Zenith 7H920 AM/FM set 7 tube - by LarryFS - 12-14-2018, 05:51 PM
RE: Zenith 7H920 AM/FM set 7 tube - by TV MAN - 12-15-2018, 11:48 AM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-15-2018, 02:16 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-17-2018, 08:13 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-18-2018, 08:25 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-18-2018, 10:01 PM
RE: Zenith 7H920 AM/FM set 7 tube - by David - 12-18-2018, 10:41 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-19-2018, 10:15 AM
RE: Zenith 7H920 AM/FM set 7 tube - by Ed Locker - 12-19-2018, 10:54 AM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-19-2018, 12:10 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-19-2018, 12:11 PM
RE: Zenith 7H920 AM/FM set 7 tube - by Ed Locker - 12-19-2018, 03:19 PM
RE: Zenith 7H920 AM/FM set 7 tube - by jcassity - 12-19-2018, 08:13 PM



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