I agree with Stuart.
Before doing anything else just change all of the diodes. They are cheap and
avaiable. You won't damage any other parts such as the meter trying to trouble
shoot the circuit and it may just fix the problem!
GL
Bill - K6WLM
________________________________
From: Stuart Rohre <rohre@arlut.utexas.edu>
To: Rick W <ve7tk@yahoo.ca>; Discussion of Ten-Tec Equipment
<tentec@contesting.com>
Sent: Sun, July 1, 2012 2:50:15 PM
Subject: Re: [TenTec] 229A SWR Circuit
Rick,
The most likely failures of any SWR measuring circuit are 1) short of
open of diodes
2) changes in carbon resistor values
3) Someone messing with, or a bad calibration pot
4) Finally, capacitors even disk ceramics commonly found, can go bad if
ever the unit took a current surge.
Check those in 1-4 order, and likely you will find something.
GL,
Stuart Rohre
K5KVH
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