[Hallicrafters] SX-28 deafness

[Mike Everette]

Given the difficulty of servicing the RF box in the
SX-28, it is probably a good idea to replace all the
resistors therein as well as the caps.

As I work on my SX-28, I am following my own advice,
to be sure. I have replaced many resistors so far, and
I am not done yet.

The original parts are sort of garden-variety, and the
resistors (at least in the 28, I have not been into a
28A) are of a type that is prone to soak up moisture. 
The metal end caps on these resistors have also been
known to get loose.

The "deafness" could indeed be due to a resistor which
checks perfectly normal with a meter but is breaking
down under high voltage.  And it sure sounds like the
first RF stage is a good place to look, along with
that particular section of the bandswitch.

If you are checking voltages in the RF section it
might be well to monitor each parameter in the suspect
stage for a few minutes apiece and see if anything
changes.

Even a "new in box" SX-28 could have some of these
problems after 65 years.  These radios are old enough
to be drawing Social Security.

73

Mike
WA4DLF

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com