[Drake] Resolved: R4B Receiver

Tue, 18 Nov 2003 09:14:53 -0500 (EST)

Just thought I'd pass along appreciation to the list and the resolution to 
the odd audio problem encountered with the R4B indicated below.  Thanks go 
to several list readers who provided insight and encouragement.  It helps!

The final culprits were C90D (100uF) and C167.  C167 had suffered some 
physical damage in a past life and would eventually open.  After careful 
inspection, I found R43 cracked which led me to suspect a leaky C90D.  I 
also ended up also replacing both C176 and C173 though both were likely 
ok. On top of the list to be replaced are the remaining sections in the 
C90 can.

Until then, I'll enjoy great Drake performance and sound!  Thanks all!

-- Paul, KG4UVU

---------- Forwarded message ----------
Date: Sun, 9 Nov 2003 22:31:49 -0500 (EST)
From: Paul Manno <[email protected]>
To: [email protected]
Subject: [Drake] R4B Receiver

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

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