[Drake] R4B Receiver

[Paul Manno]

Hello all,

I recently received an R4B receiver with a low-audio condition.  All tubes 
have been checked swapped and replaced, the voltages seem correct to the 
manual data at the audio stage (transistor and 6EH5).  Speaker is 4 ohm.

After the unit is first turned on after a long (few days) off-time, audio 
output is near normal for a few minutes then the audio drops suddenly to 
about 25% former volume with no pop or crackle.  After that, if the audio 
gain control is turned up past the 3:00 position, audio becomes distorted 
but rcvr never attains the first-on volume level.  It appears someone has 
already replaced the 10uf electrolytic in the 6EH5 cathode circuit.

The RF seems to behave normally (S-meter shows same signal levels) before 
and after the audio volume drop.  I have observed the 6EH5 seems to run 
very warm but I don't know if that's just the tube.

I do appreciate your suggestions where to start looking.

Tnx and 73,
-- Paul, KG4UVU