[Hallicrafters] SR-2000 Post Production EC

[Jim Liles]

Received the fifth call in as many Months regarding a high noise level that 
occurs under several conditions.
1. Switching the HV on or switching to Hi power
2. Resonating the pre-selector.
3. You think the radio is really hot because without an antenna resonating 
the pre-selector
    results in a significant rushing noise --- it's not hot just broken.
4. Makes a lot of noise when going from transmit to receive.

The fix is simple.  Replace CR1 a 1N458 with a 1N459A.  What's happening is 
CR1 has been punctured and leaks causing current to flow in R146 --- a great 
noise generator.  CR1 is used to quench any RF that breaches the T/R relay 
from getting into the receive front end and is gated off with back -90V in 
receive mode.  The 1N458 was a bad choice for that component.  The 1N459A 
will not fail.  If this is not clear or you have questions call home 
847-913-8576 or cell 847-571-8420
Kindest regards Jim K9AXN