From: "Carel, PA0CMU" 
Subject: Re: [drakelist] TR7 mode switch thump. PROBLEM FOUND


"Carel, PA0CMU"  made an utterence to
the drakelist gang
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Hi all,

The problem of the mode switch thump has been found.
On the early version of the 2nd IF/Audio Board, R1187 doesn't exist. On the 
late version board Drake added R1187 (10K) in series with CR1119 but made a 
mistake in the copper trace design. In some (or most ?) cases, R1187 is 
short-circuited! Switching to CW mode still charges C1151 (22uF/16V) 
immediately through CR1119, thus giving a loud click in the audio circuit.

I added a 10k resistor to my early version board and Rien - PA0TRT, modified 
the copper trace of his late version board. Both TR7's (S/N 3157 and 9345) 
are switching without any click to CW mode now.

73, Carel - PA0CMU.

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