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Antique Radio Technical Forum
Crackling problem solved, but can't receive stations.

Posted by Terry Decker on 01/30/2010 13:20


I was showing off my AM transmitter and this GE 515(F?) displayed a loud crackling noise before the volume control. A posting here on Nostalgia Air made me aware of the IF mica cap breakdown, along with a great link on how to effect the repair, which I did. I followed the schematic, but this poor set has had dozens of design changes and that can’t always be trusted.
I’ve replaced the IF caps with 75pf, which is what the schematic calls for. Anticipating some B+ bleed I also replaced the 22KÙ between pins 1 and 2 of the 12BE6, and the 120Ù resistor and 47pf cap from pin 1 to the osc coil. I’ve also subbed the tube with a known good one. I’ve documented every change on paper and with photos. I have the following voltages-
Pin #1, (G1) minus 3 VDC
Pin #2 (K, G5) Plus 10 VDC
Pin #5 (P) 80 VDC
Pin $6 (G2, G4) 80VDC
A 455kc modulated signal from my IG-102 plays through the set all the way from the antenna, and adjusting the IF cans does make a difference in the output. I tried injecting the 455 signal as an osc source and tuning the signal generator to 1425 for a signal at 970, but without a freq meter, (one is on its way), it was a shot in the dark. I’m also in the dark in this area, so I might not be doing it right. I don’t have a lot of experience messing with the IF section, most of the sets I work on have other problems.
SO-Everything seems to work but I can’t receive any stations. It obviously has something to do with the IF can repair, but I’m lost as to what. Any advice would be GREATLY appreciated. This forum has come through many times, I hope it can help here. Oh yeah- the crackling noise has disappeared.
Thanks,
Terry



IPAddress: ***.28.48.106


Crackling problem solved, but can't receive stations. 
Terry Decker 01/30/2010 13:20 
Bill G. 02/01/2010 18:22 
Terry Decker 02/01/2010 18:55 
Thomas Dermody 02/01/2010 19:12 
Thomas Dermody 02/01/2010 22:29 
Terry Decker 02/01/2010 23:21 
Thomas Dermody 02/02/2010 03:41 
Terry Decker 02/02/2010 23:23 
Thomas Dermody 02/03/2010 01:52 
Peter G. Balazsy 02/03/2010 02:15 
Thomas Dermody 02/03/2010 12:10 
Terry Decker 02/03/2010 23:30 
Thomas Dermody 02/04/2010 01:27 
Peter G. Balazsy 02/04/2010 03:14 
Terry Decker 02/04/2010 12:41 
Edd 02/04/2010 16:46 
Terry Decker 02/04/2010 17:13 
Thomas Dermody 02/04/2010 19:10 
Peter G. Balazsy 02/04/2010 23:02 
Terry Decker 02/04/2010 23:52 
Terry Decker 02/05/2010 00:01 
Peter G. Balazsy 02/05/2010 01:29 
Warren 02/05/2010 02:06 
Edd 02/05/2010 04:44 
Thomas Dermody 02/05/2010 06:50 
Peter G. Balazsy 02/05/2010 06:50 
Bill G. 02/05/2010 11:17 
Terry Decker 02/05/2010 12:45 
Marv Nuce 02/05/2010 13:18 
Terry Decker 02/05/2010 14:50 
Thomas Dermody 02/05/2010 17:46 
Marv Nuce 02/05/2010 21:10 
Terry Decker 02/05/2010 23:26 
Marv Nuce 02/06/2010 00:24 
Marv Watcher 02/07/2010 04:39 
Marv Nuce 02/07/2010 13:30 
Terry Decker 02/07/2010 13:47 
Cindy to Terry 02/07/2010 15:45 
Marv Nuce 02/07/2010 18:13 
Thomas Dermody 02/07/2010 19:06 
Marv Nuce Watcher 02/08/2010 04:16 
Thomas Dermody 02/08/2010 07:27 
Marv Nuce 02/08/2010 13:25 
Peter G. Balazsy 02/08/2010 01:32 
Terry Decker 02/08/2010 12:13 
Edd 02/09/2010 03:23 
Terry Decker 02/09/2010 13:07 
Peter G. Balazsy 02/09/2010 23:13 
Terry Decker 02/10/2010 10:52 
Thomas Dermody 02/10/2010 00:41 
Peter G. Balazsy 02/10/2010 02:04 
Thomas Dermody 02/10/2010 09:35 
Terry Decker 02/11/2010 18:33 
Peter G. Balazsy 02/11/2010 22:08 
Thomas Dermody 02/12/2010 00:26 
Peter G. Balazsy 02/12/2010 14:27 
Terry Decker 02/12/2010 19:52 
Peter G. Balazsy 02/17/2010 04:22 
Terry Decker 02/17/2010 12:49 
Terry Decker 02/17/2010 12:54 
Thomas Dermody 02/17/2010 18:42 
Peter G. Balazsy 02/20/2010 03:10 
Terry Decker 02/20/2010 13:41 
Terry Decker 02/24/2010 23:11 
Cindy 02/25/2010 01:19 
Marv Nuce 02/25/2010 15:56 
Terry Decker 02/26/2010 00:27 
Terry Decker 03/06/2010 12:52 

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