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Old February 12th 06, 07:16 PM posted to uk.radio.amateur,rec.radio.amateur.homebrew
Samuel Hunt
 
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Default FT-757 GXII alignment....

Has anyone any info on servicing one of these?

The power control is out of alignment (about 3/4 of the way up it suddenly
jumps into TX at full power, with it being very sensitive to get any control
between full and no power).

Possibly a bias problem on the PA?

And the power meter needs re-aligning.

And the FM deviation is too high.

Can anyone point me towards the internal pots?


Thanks,

Sam
M1FJB



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Old February 12th 06, 07:40 PM posted to uk.radio.amateur,rec.radio.amateur.homebrew
G4ZWI
 
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Default FT-757 GXII alignment....

Hiya Sam, I had one of these, I am sure the FM pot is on the 'local'
board, which is the one with the patch/ptt/CAT sockets on. VR02 I am
sure, and it feeds the fm af amp transistor, q2008. As for the power
control, they are very 'jumpy', all on or off, and very narrow over the
operating range, sure yours is just as they are. I also still have the
mobile mount for it in the loft, I think!!!!!!!!
Cheers, Fred G4ZWI

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Old February 12th 06, 07:44 PM posted to uk.radio.amateur,rec.radio.amateur.homebrew
Samuel Hunt
 
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Default FT-757 GXII alignment....

Hi Fred...


Ah, never mind then, I'll have to live with it (well not me, I'm asking on
behalf of a friend).

Any ideas about the meter though, that needs re-calibrating.


Sam

"G4ZWI" wrote in message
oups.com...
Hiya Sam, I had one of these, I am sure the FM pot is on the 'local'
board, which is the one with the patch/ptt/CAT sockets on. VR02 I am
sure, and it feeds the fm af amp transistor, q2008. As for the power
control, they are very 'jumpy', all on or off, and very narrow over the
operating range, sure yours is just as they are. I also still have the
mobile mount for it in the loft, I think!!!!!!!!
Cheers, Fred G4ZWI



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Old February 12th 06, 08:03 PM posted to uk.radio.amateur,rec.radio.amateur.homebrew
G4ZWI
 
Posts: n/a
Default FT-757 GXII alignment....

Never had to tweak that one Sam. There is a preset near the meter
driver circuit, (An6552, Q51, on the R.F. board.) That may be the one.
There is a 'pot' to set the FSD of the meter on Tx (for SWR forward
reading, obviously you set it to full scale, then set the swr switch to
reverse.) It is not that this control has been set too far up?? (Its on
the back of the unit, under the antenna socket, marked 'fwd set'?)
Best of luck, mate, I have got a few bits of cct diagrams if you are
really stuck, and may help....
Fred

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Old February 13th 06, 02:10 AM posted to uk.radio.amateur,rec.radio.amateur.homebrew
mikeFNB
 
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Default FT-757 GXII alignment....

the full ervice manual is on mod.dk site
the power variable on the front panel always was 'iffy' though a squirt of
cleaner (not WD40) might help.
dont forget as the other gent says, the SWR pot on the back will effect the
meter PO scale.
also it is caled into 50R so will not read correct of an aerial or ATU. as
such.

if you wish help
pse ask

done loads and own one since 1985

mike

"Samuel Hunt" wrote in message
...
Has anyone any info on servicing one of these?

The power control is out of alignment (about 3/4 of the way up it suddenly
jumps into TX at full power, with it being very sensitive to get any
control between full and no power).

Possibly a bias problem on the PA?

And the power meter needs re-aligning.

And the FM deviation is too high.

Can anyone point me towards the internal pots?


Thanks,

Sam
M1FJB





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Old February 13th 06, 08:55 AM posted to uk.radio.amateur,rec.radio.amateur.homebrew
 
Posts: n/a
Default FT-757 GXII alignment....


Samuel Hunt wrote:
Has anyone any info on servicing one of these?

The power control is out of alignment (about 3/4 of the way up it suddenly
jumps into TX at full power, with it being very sensitive to get any control
between full and no power).

Possibly a bias problem on the PA?

And the power meter needs re-aligning.

And the FM deviation is too high.

Can anyone point me towards the internal pots?


Thanks,

Sam
M1FJB


Have a look on this url, the full workshop manual can be downloaded for
free

http://foxtango.ham-radio-op.net/Eighties/Eighties.htm

regards

Dave

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Old February 13th 06, 09:07 AM posted to uk.radio.amateur,rec.radio.amateur.homebrew
Brian Reay
 
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Default FT-757 GXII alignment....


wrote in message
ups.com...


Have a look on this url, the full workshop manual can be downloaded for
free

http://foxtango.ham-radio-op.net/Eighties/Eighties.htm


That is a useful link.

I see they have manuals for the FT101 as well:

http://foxtango.ham-radio-op.net/FT101/FT101.htm

Wasn't there someone who couldn't tune the PA on one of these as some pages
were missing from his manual?

__
73
Brian
www.g8osn.org.uk



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Old February 13th 06, 09:40 AM posted to uk.radio.amateur,rec.radio.amateur.homebrew
Spike
 
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Default FT-757 GXII alignment....


Brian Reay wrote:


I see they have manuals for the FT101 as well:

http://foxtango.ham-radio-op.net/FT101/FT101.htm

Wasn't there someone who couldn't tune the PA on one of these as some pages
were missing from his manual?


Isn't that the same chappy who's radio scheme enjoins potential
candidates to 'repair their rigs with gusto' (or some such claptrap
phrase) but neglects to mention that he only advises they do so to
low-powered transistorised rigs, and avoids compact valve PAs with
600VDC on the anodes?


from
Aero Spike
  #9   Report Post  
Old February 19th 06, 12:44 PM posted to uk.radio.amateur,rec.radio.amateur.homebrew
Plod's Conscience
 
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Default FT-757 GXII alignment....

Wasn't there someone who couldn't work out the trivially simple
task of how to thread a wire through the tubes of a roof rack?

Brian Reay wrote:
Wasn't there someone who couldn't tune the PA on one of these as some pages
were missing from his manual?


  #10   Report Post  
Old February 19th 06, 01:07 PM posted to uk.radio.amateur,rec.radio.amateur.homebrew
Plod's Conscience
 
Posts: n/a
Default FT-757 GXII alignment....

Wasn't there someone who couldn't achieve the trivially simple
task of differentiating between the male and female version
of Anderson "Power Pole" connectors?

ISTR it was the same fool who couldn't tell one end of the
resistor colour codes from the other and hence posited that
resistors were polarised?

What a silly boy!


Brian Reay wrote:

Wasn't there someone who couldn't tune the PA on one of these as some pages
were missing from his manual?




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