From: Eric Webner 
Subject: Re: [drakelist] TR7 Display Problem


Eric Webner  made an utterence to the drakelist gang
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Bud,
 
How did you guys determine that it was the choke. Did the core crack from
physical damage, or did it go intermittant or , , , ?
 
73,
 
Eric KA8FAN

Garey Barrell  wrote:

Garey Barrell made an utterence to the drakelist gang
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Wow! Talk about obscure....

The ONLY thing this choke does is filter the 24V supply to the PLL Loop 
amplifier chip, so the VCO was yanked way out of it's "normal" range. 
I _TOLD_ you we needed to measure the loop error voltage....! :-) 
Yeah, right. At least now we know it really WILL go that high.

Thanks for the feedback!

73, Garey - K4OAH
Atlanta

Drake C-Line Service Manual




sebdesn wrote:

>"sebdesn" made an utterence to the drakelist gang
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>Well finally,,,,
>
>Wanted to post the resolution for the archives in case anyone else has this
>problem.
>Many thanks to Bill Frost who had the final answer, and Garey Barrell, and
>Peter VE3AX for some good troubleshooting suggestions.
> The rig showed 96800.0 on powerup(20m and below) and drifted down
>slightly. VFO did not change anything. Counter worked properly in
"ext"mode.
>All voltages from p/s board were OK. 10R and 10T on main board were ok and
>switched properly xmit/ rcv. All oscillator freqs were there and right on.
> The problem was choke RFC508 which is in the 24v circuit to the VCO
>board.It is on the VCO board and is in a position that could be easily
>damaged inserting the board. Replaced that, fired things up, and all is
>well. Will align and put on the air..
> Again thanks to all who helped. This is a great list and in my case, a
>real lifesaver!!!
>
>73,de Bud WØHG
> 
>
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Bud,
 
How did you guys determine that it was the choke. Did the core
crack from physical damage, or did it go intermittant or , , ,
?
 
73,
 
Eric KA8FAN
Garey Barrell
<k4oah{at}mindspring.com> wrote:
Garey Barrell
made an utterence to the drakelist
gang----------------------------------------------------------------------Wow!
Talk about obscure....The ONLY thing this choke does is
filter the 24V supply to the PLL Loop amplifier chip, so the VCO
was yanked way out of it's "normal" range. I _TOLD_ you
we needed to measure the loop error voltage....! :-) Yeah, right.
At least now we know it really WILL go that high.Thanks
for the feedback!73, Garey -
K4OAHAtlantaDrake C-Line Service
Manual<HTTP: R-4C_Servicez hr99.home.mindspring.com
/>sebdesn
wrote:>"sebdesn"
made an utterence to the drakelist
gang>---------------------------------------------------------------------->Well
finally,,,,>>Wanted to post the
resolutio!

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