[Drake] TR7 problem (long)

[Neil Rosenberg]

The TR7 has a habit of developing bad contacts.  Sometimes in the band 
switch wafers, sometimes in the front panel switches, sometimes in the 
connectors on the plug in boards.  First line of defense is to unplug 
everything, shoot some deoxit and replug.

Works very often.
Neil

At 10:25 PM 11/7/2004, HENRY PFIZENMAYER wrote:
>OK gurus , any ideas ? Digital stuff is beyond my analog training. I know
>enough to be dangerous.
>
>
>Was transmitting on 21025 running a test cw loop and watching tv in next
>room. I went back to the TR7 and it still had the cw side tone , but no rf
>output and the DR7 readout was something like 11000 khz ( At the time I did
>not think to write it down) .
>
>Switched the bandswitch and it came back and operated ok. Then operating in
>CWSS contest , was intermittent one time Sat but ran all night on 80 meters
>cw. When first turned back on Sun Am it was normal , turned it off to do
>some things and when turned it back on it was back to the 11000 khz readout
>, tried switching bandswitch , the up and down frequency buttons , the aux
>switch , the counter switch etc  and no change , then all of a sudden the
>DR7 readout went blank with only the decimal point lit like when you switch
>to the frequency counter. Nothing would bring anything back so I opened it
>up and still no DR7 readout , seemed like receiver was active but no idea
>where it was listening , the calibrator level was normal.
>
>I was pushing on the DR7 board , tapped some of the ics and parts etc and
>nil , then pushed on the front panel by the frequency up/down switches and
>the thing came back to life , I put the covers back on and it worked all day
>for rest of  SS.
>I couldn't see anything touching chassis or whatever around the freq
>switches.
>
>Looking at the TR7 service manual and some Drake notes , nothing fits this
>problem very well. I get a feeling from reading that it  might be something
>intermittent on the digital control board under the DR7 , but before I dig
>in and remove the DR7 to look , any ideas from the group????
>
>First real big problem in 24 years with my faithful TR7 !.
>
>
>Thanks
>
>  Hank K7HP
>
>
>
>______________________________________________________________
>Drake mailing list
>Home: http://mailman.qth.net/mailman/listinfo/drake
>Help: http://mailman.qth.net/mmfaq.html
>Post: mailto:Drake at mailman.qth.net