Drake Home Page       Drake Technical Tips Menu

R4 R4C INJECTION LEVEL PROBLEM

By:  Mark Gilger / WB0IQK

Drake R-4C Receiver

Symptom:  Receiver sensitivity was about half what it should be. Switching over to the T4XC VFO and the sensitivity was normal.

Fix:  Diode CR5 located between V6 plate and grid was defective. Its very hard to get to this diode, so care must be taken not to damage any of the surrounding parts. 

 

 

  

Drake R-4B Receiver

Symptom:  Power output was lower when operating off of the receivers VFO than the T4XB.

Fix:  R46, R103, C34 could have changed value.

 

Drake R-4 Receiver

Symptom:  Power output was lower when operating off of the receivers VFO than the T4X.

Fix:  R7, C20, or C136 could have changed value.