[Collins] Need some KWM-1 help

[Dr. Gerald N. Johnson]

On Wed, 2006-04-19 at 12:31 -0500, pmills7 at houston.rr.com wrote:
> I am having my first ever hands-on experience working on a KWM-1 for a 
> friend.
> When first powered up, there is a short delay of 5 seconds or so then vox 
> relay k2
> closes and activates relays k1 and k3.  After about another 10 seconds or so 
> as
> the set warms up, relay k2 opens and releases k1 and k3.  I have measured 
> the grid voltage on V16B which is the vox relay control and it is zero. 
> This sequence does not happen if V16 is removed from its socket.  Is this 
> normal operation for a KWM-1?  If not, can anyone suggest what might be 
> causing the problem.....I have tried a new 6U8 for V16 and that did not 
> change anything.
> 
> thanks for any and all advice and help, 73,
> Phil
> W5BVB
> 
Check the V16 cathode voltage. I think its low. Check C115 and C179 for
leakage. C115 is likely a black beauty and most surely is leaky. Check
C180 for leakage too. Old electrolytics tend to be bad. Be sure the VOX
switch is open (on the VOX gain pot).


-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer