[Yaesu] FT-747GX Hookup To LA-1000A Amp

[Thomas Giella]

  Recently I purchased a Yaesu FT-747GX made in January 1991, for mobile =
use. I've been trying to make my Amp Supply LA-1000A linear amplifier =
work with the FT-747GX but to no avail. The operations manual says =
output from transistor to pin #6 and pin 2 ground of the FT-747GX female =
band data plug should key a linear amplifier relay. I'm sending output =
of pin #6 to the center pin of the LA-1000A RCA female relay jack input =
and pin #2 to the ground of the RCA female relay jack input.=20
  I've also come to realize that a regular 8 pin DIN plug also does not =
fit the FT-747GX band data female plug but does on an FT-990. Also on an =
8 pin DIN plug center pin is numbered 8 but the FT-747 schematic seems =
to show the center pin as #6 but no matter. I tried center pin #8 as a =
pin #6 and real pin #6 and real pin #8 but no luck. I checked all =
involved transistors and diodes in the area of the jack and all seem to =
be okay. I have not checked the relay though.
  As I'm half blind in one eye and deaf in the other:<) I might be =
overlooking something. I wonder if the FT-747GX requires the FRB-757 =
relay interface box that Yaesu sells? I do not have this problem with my =
FT-990 and LA-1000A.=20
  Also I read in an ARRL QST magazine review of the FT-747GX published =
in August 1989, that there was a tech. supplement to be put out by Yaesu =
concerning improving receive audio bandwidth by removing just one =
capacitor. The mod was supposed to increase SSB audio bandwidth from =
1246 hz to 2100 hz. Can anyone send me info on this mod?
  Lastly whether in transmit or receive the the rig frequency jumps +/- =
500 hz but does not show up on the frequency readout display. Could be a =
problem with the TCXO unit? Any ideas?
  Any input would be much appreciated.



73,
Thomas Giella , KN4LF
EL87WX
Plant City, FL USA

Florida Space & Atmospheric Weather Institute:
http://www.kn4lf.com/fsawi.htm

Friend Website Design Studio:
http://www.kn4lf.com


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