[Heath] DX100 Question

[T. David Cohen]

Many thanks to everyone who provided me with technical information on the
DX100.   This group is an awesome resource.   The problem, at least with the
audio driver, is now solved.   Who would have thought the coupling cap
between the 12AX7 and the grid of the 12BY7 would have had a high resistance
short (for goodness sake, the cap is a mica part - they're supposed to last
forever)?  With no voltage applied, the grid to ground resistance on the
12BY7 was fine.  Things were not so good when the circuit was powered since
there was a POSITIVE bias on the driver tube.   This is likely what caused
the driver transformer to fail.

 

Again, thanks for the help.  I'm sure I'll have more questions as the
process of getting this sixty year old transmitter up and running.

 

Dave, N7TC.

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