no audio after switch on

[Karl Altmann]

Response to DB3LMN and G3RXQ.


Philip and Stewart

my K2/4477 shows the same strange sffect. I found out: AGC goes up, blocking the IF-Amp; S-Meter shows full deflection, can
be checked at the AGC-Amp U2A pin1. Touching that  IC with your fingertip acts like a reset. Changing the IC did not cure the
problem. I observes it mainly at switch on, but also sometimes "in between". Will try to find out what is going on there. Otherwise
we have Gary!

73, Karl.  oe3tl.
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[Don Wilhelm-3]

Karl,

Try re-soldering things - particularly U2, Q12, D1, R3, and R5.  The normal
voltage at U2 pin 1 is 3.7 to 3.8 volts for most K2s.  A solder joint that
looks good, but has some resistance could cause that sort of problem - and
the resistance can change with temperature, so results are unpredictable.

73,
Don W3FPR

----- Original Message -----

my K2/4477 shows the same strange sffect. I found out: AGC goes up, blocking
the IF-Amp; S-Meter shows full deflection, can
be checked at the AGC-Amp U2A pin1. Touching that  IC with your fingertip
acts like a reset. Changing the IC did not cure the
problem. I observes it mainly at switch on, but also sometimes "in between".
Will try to find out what is going on there. Otherwise
we have Gary!



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