[Kenwood] TS-850SAT receiver noise problem

[Brian Mileshosky]

Hi Everyone -

 

I'm having a receiver noise issue with my TS-850SAT, and I'm looking for
ideas on what it might be.  My 850's serial number is 30-million series.
According to some (unverified) information I found on the web, it looks like
this might correspond to having been built in 1991.

 

Here's the problem:

 

--- My 850 is experiencing loud, intermittent, crashing, static-like pops in
the receiver.  Sounds like static crashes from nearby lightning strikes.

--- I've confirmed that the noise is originating from within the radio, and
no external sources, as I've operated the radio with a 50-ohm load connected
to the antenna port (as well as an open), on battery power, and no cords or
cables other than the power cable attached to the radio.the crashes still
occur.

--- The crashes register on the S-meter, which tell me that it's occurring
in the receiver chain prior to when signal is coupled into the S-meter.

--- The crashes get louder (and stronger on the S-meter) as I tune to lower
frequency bands, which makes sense.

--- I have not been able to correlate the occurrence of this noise with
temperature.  Seems somewhat random as far as when the problem begins after
I turn the radio on, and also when the crashes occur.they range from once
every 10 sec to sometimes more than once a second.

--- I've looked at each of the LOs in the receiver with an o-scope and they
are both on frequency and look clean.

--- Poking elsewhere in the receiver chain with my o-scope hasn't shown any
apparent noise at the time I hear crashes on the speaker.

 

Any ideas?

 

Thanks and 73,

Brian N5ZGT