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Antique Radio Technical Forum
Zenith T825: No FM, just static

Posted by Mark Johansson on 02/19/2008 22:28

Hi Bill,

Thanks for the hints! I checked the voltages as you suggested. Pin 1 of the 12AU6 is -4.82 volts but pins 1 & 2 on the 19T8 are hovering around + .04v. Also, pin 3 which is supposed to be -.5 v is +13v. Could this mean problems with the caps in the discriminator can?

Thanks, Mark
::
:Hi Mark,
: Your schematic looks better than the ones on this site.
: To check out my hypothesis, check pin 1 oa the 12AU6 and pins 1 and 2 of the 19T8. Voltages need to be negative. If they are a little different from the voltages shown don't worry about it, but these voltages must not be positive.
: Usually a positive at one of these points is indicative of Silver Mica Disease in the IF transformer in the previous stage.
: Let me know what you find on the voltage measurements. We can go from there.
:
:Best Regards,
:
:Bill Grimm



Zenith T825: No FM, just static 
Mark Johansson 02/13/2008 17:12 
{:o)<= 02/14/2008 16:12 
Edd 02/14/2008 16:55 
Thomas Dermody 02/14/2008 17:37 
Bill G. 02/14/2008 17:55 
mark Johansson 02/15/2008 12:47 
Bill G. 02/15/2008 13:43 
Mark Johansson 02/19/2008 22:28 
Bill G. 02/20/2008 08:33 
Mark Johansson 02/20/2008 22:38 
Bill G. 02/22/2008 15:34 
Thomas Dermody 02/22/2008 17:42 
Al R. 04/14/2009 09:18 
Bill G. 04/14/2009 09:55 
Al 04/14/2009 12:37 

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