[NLRS] Interfacing a TR751

[Mike King - KM0T]

John and all,

I have modified two seperate TR751s to get rid of the funky connector on the 
back.  It does involve takeing the entire back panel off which contains the 
amp module and has all kinds of multi pin connectors.  I had a schematic to 
help me track down the right wires on the funky connector and just cut the 
alc line.  The PTT is a single wire to ground via an internal relay.  I 
drilled out the funky connector hole and put in a RCA connector, worked real 
good, but I never knew if it was going to work until I put it all back 
together and powered it up :)  It was somewhat of an adventure!

I have schematics, but it may take me a few days to get them scanned and 
emailed if you need them.  Let me know.

73

Mike - KM0T

----- Original Message ----- 
From: <W0ZQ at aol.com>
To: <nlrs at mailman.qth.net>
Sent: Wednesday, October 24, 2007 5:30 PM
Subject: Re: [NLRS] Interfacing a TR751


>
>
> Donn has it right.   My TR751A has a  funky four pin ACC connector in the
> back where the pins are in a diamond  configuration with the fourth pin in 
> the
> middle of the triangle.    Looking at the schematic, the two pins that 
> form the
> SPST switch are at 12  o'clock and 4 o'clock.  This is a normally open 
> relay
> contact that shorts  on PTT.  The pin in the center of the diamond is 
> chassis
> ground while the  pin at 8 o'clock is ALC input.   You should be able to
> confirm this  with an ohm meter.   I would suggest that you modify the rig 
> and get
> rid of that funky connector.
>
> 73, Jon
> W0ZQ
>
>
>
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