[R-390] R-390A Noise Limiter not working

[Larry H]

As mentioned in a recent previous post, the Noise Limiter was not working
in this IF deck I'm working on.  Although I found numerous problems with
the components, the failure was not a component.  It was a 100k ohm phantom
resistor between V907A pins 1 & 2 and the audio input to the NL at R527.
This was caused when someone replaced the .0l mfd C549 (the NL output) with
a .05 mfd orange drop.  When soldering it to the bottom terminal, the audio
input line got caught.  This phantom 100k resistor effectively routed the
input to the output, rendering the NL inoperative.

Fixing that allowed it to work, but not up to specs.  The 4 main resistors
R532 through R535 measured 25% to 35% high and C532 had very bad leakage.
These issues did not allow enough current in the NL to pass the audio at
low signal levels.  Once replaced, the NL is now working correctly.

BTW, C532 is a 100 pf mica.

Regards, Larry