[Heathkit] SB-220

[wb8jkr at juno.com]

  Probably a dirty relay contact. The bias should
switch between about -100 volts and -5 volts
between rec & xmit.

Mark  WB8JKR


On Thu, 25 Nov 2004 11:06:31 -0500 "Don Flenner" <w4ych at earthlink.net>
writes:
> Greetings All and Happy Thanksgiving,
> 
> I recently acquired a SB-220 in a non working condition...The 
> problem is:
> 
> When the antenna change over relay is energized I get no idling 
> plate 
> current...
> 
> The 3-500Z's light up, I have checked them in another amp and get 
> the proper 
> idling plate current, the plate voltage reads 2500 in tune and 3200 
> in SSB. 
> I have changed the 5.1 volt zener, checked the wiring of the antenna 
> relay. 
> The plate current meter deflects when a put an ohm meter across it, 
> so I 
> amuse the meter is OK.  Also, as a further test to make sure it was 
> not a 
> meter problem. I hooked the amp to a transceiver. With the amp off I 
> get 100 
> watts out. When I turn the amp on and press the PTT, the relay 
> energizes in 
> the amp but no output.
> 
> Sure could use some guidance from the knowledgeable on this 
> reflector.
> 
> Thanks in advance.
> 
> 
> 73,
> Don, W4YCH
> http://www.home.earthlink.net/~w4ych
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
>