[Milsurplus] T-195 TR delay

B. Smith smithab11 at comcast.net
Wed Mar 25 20:07:48 EDT 2009


    Thanks to all that responded. I found a 2.7 megohm (R448) in the bias 
feed to the delay tube V403 in the modulator that had aged way out of 
tolerance . I know what does the modulator have to do with TR 
switching --beats me but that where V403 a 12AT7 is because half is used as 
a sidetone amplifier and the other half is the delay tube.        Anyway I 
put  another resistor in paralled with R448 and now the bias can charge up 
the 4 uF cap C424 and provide cutoff of the tube in a timely manner.
    So went from a 4.5 second TR delay to about 1.2 seconds which is close 
enough for government work and still allows the other zillion relays  in the 
T-195 to switch over in sequence.

73
breck k4che 



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