TS450S.2

Intermittent receive fixed.
After  making a careful mobile installation, WB0BQV found his TS450S  to  have 
intermittent receive. He removed the screw that was going through the coax  in 
his  car and made a second installation in his truck. More intermittent.  With 
some  careful  diagnosis he found that moving the coax connector up  and  down 
caused the change in signal. With the radio opened up, I found that moving the 
coax  connector  was  breaking the contact between the wire  from  the  center 
conductor  and the board (W1 in the schematic). To save on pulling the  filter 
board,  I used a short piece of very flexible test prod wire to  connect  from 
the  center  of the UHF connector to W6 on the top of the PC board.  W6  jumps 
over  the contacts of a relay used only in the TS-690S. For added security,  I 
also  added another wire of the same material from the ground lug on  the  UHF 
connector  to  the  end of D11 away from the coax connector.  So  now  if  the 
flexible  back panel breaks the other wire too, it won't have so much  effect. 
The coax connector is mounted on a 1/32" plated steel panel so is  excessively 
flexible  in  mounting.  Ideally that connector should  be  mounted  far  more 
stiffly for those that use real RG-8 coax.

by K0CQ