Don't overlook the TR relay. A similar problem many years ago was caused by
a solder splash across the lugs of the TR relay on a then newly built SB220.
Try checking relay function with an ohmeter with the AC disconnected and the
caps discharged.
Best of luck!
WA4TUK
-----Original Message-----
From: bob alexander <realex@flash.net>
To: <amps@contesting.com>
To: <amps@contesting.com>
Date: Thursday, December 24, 1998 5:41 PM
Subject: [AMPS] SB-200 problem
>
>Howdy,
>I've been troubleshooting an SB200 and have gotten exactly
>nowhere. Measured operating conditions are:
>
>Plate voltage = 2100 indicated on front panel meter
>(I've measured 350 VDC +/- 10% across each filter cap)
>there is continuity between p.s. and plates (no open choke)
>
>Bias (measured between grid and cathode) = -125 VDC in standby,
> -2 VDC keyed
>
>Idle current = 20 Ma indicated
>
>Plate current = 100 Ma with 100 Watts drive
>
>Power output = 100 Watts max on any band
>
>Input VSWR between 2 and 3:1 depending on band
>
>Filament voltage = 6.31 VAC (center tap is grounded)
>
>All components check O.K.
>
>I get the same results with a second set of 572Bs
>
>Does anyone have any suggestions?
>73, and Thanks
>Bob, W5AH
>
>--
>FAQ on WWW: http://www.contesting.com/ampfaq.html
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
>
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
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Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
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