Max -
Yes, the intermittent hum is quite likely in the resistor/capacitor area
you describe. Also check the board mounting screws to make sure they
are tight. I'm not aware of any replacement boards aside from a donor
unit. A failed (shorted) filter cap (sometimes with an oversize fuse
installed when the leakage started to blow the correct fuse) is what
usually causes this problem.
There should be NO cracking or popping of the AVC. First check is the
'Bias & S-Meter' alignment in the manual, especially the 'receiver
sensitivity' trimpot. Near the center of the chassis, about 5" behind
the front panel.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-B, C-Line&
TR-4/C Service Supplement CDs
<www.k4oah.com>
AirRadio wrote:
My R4B which I was refurbing for this W/E CQWW has a couple of issues,
firstly the power supply intermittently hums, I can see that the Cap
is loose on the power supply board and the resistor has been badly
replaced so is probably the problem there, is there an upgrade board
available as this one has lost some tracking, the other is the AGC in
fast and slow there appears to be a certain amount of distortion and
cracking on speech peaks, is this normal or do I have a problem here,
don't want to investigate this if is a normal occurance.
thanks in anticipation,
Max
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