[QuadList] Weekend Mystery Pic for 3/12/11

[W4wj at aol.com]

Strange...  I don't remember this button on  our
AVR3's...  Must be a senior VTR moment!!  Also I  don't 
remember any tracking problems either with  in-house 
or outside tapes...
 
As I mentioned before...  Next to the AVR-1, the  AVR-3
was my second favorite Quad, just ahead of the
VR-2000B!
 
 
Don Murray, W4WJ
Retired from 40 years of Miami TV Engineering
35+ years at NBC O&O WTVJ
 
 
 
In a message dated 3/13/2011 10:18:37 P.M. Central Daylight Time,  
dwnorwood at embarqmail.com writes:

There has been deafening silence on this pic except for the reply from  
Chris and an off-list, correct answer from David Crosthwait.   Congratulations 
again David!  With the weekend coming to a close, I'll go  ahead and post 
the answer along with the "rest of the story".
 
The control is the tracking adjustment on an AVR-3.  The story  behind the 
control is really interesting and was told to me a while back by  fellow 
list member Bill Carpenter.  Below is what Bill had to  say.......
 
This control was added in the "massive retrofit", which I had to  start to 
correct all the problems.

The tracking control was there, but  we needed a front panel pushbutton, 
which turned on and off the very poor  autotracking. 

I can't remember whether it turned the autotracking on  and off, or whether 
it just told it to track again!

The control came  from the Tektronix 7000 series scope, and I arranged to 
buy the controls from  Tek, to solve the problem, and not add another control 
as part of the  retrofit.

The original design by a well known industry servo design  engineer, would 
turn ON the dither, find track center, and then freeze that  position, and 
turn dither OFF.

This is fine for a long tape which was  to playback "to air". 

The Hollywood post production marketplace had  over 50 machines, and they 
found out that the source reels which would have  many "takes", a few seconds 
long, maybe 30 seconds at best would only track on  the first "take", and 
then mistrack on most of the others, since the Record  machine had been 
started and stopped after every take!

This all  happened because the Product Manager had no experience in the 
Hollywood  marketplace, and was also worrying about the Editing system we were 
going to  buy from Central Dynamics in Canada, but that's another long sad 
story, for  another day!

We made the Autotracking work, after the retrofit, with  the control which 
I sourced from Tek.
.........................
 
So, when Chris wondered if it might be part of a vectorscope, he  was 
almost on the right track!  I have some of these controls on a  Tek 7000 series 
instrument, but this pic was from an AVR-3 and was sent to me  by list member 
John Pommon.  Thanks John!  A bit of work in  Photoshop eliminated the 
"Tracking" label on the panel and turned it into  B&W to hide the panel color.  
The AVR-3 doesn't get much discussion  on the list, but it had been active 
recently so I thought it would be a good  time for this one.  Next week, off 
in a different direction........
 
Don Norwood
Digitrak Communications, Inc.
_www.digitrakcom.com_ (http://www.digitrakcom.com/) 

----- Original Message ----- 
From:  _Don Norwood_ (mailto:dwnorwood at embarqmail.com)  
To: _Quad List_ (mailto:quadlist at quadvideotapegroup.com)  
Sent: Saturday, March 12, 2011 12:40  PM
Subject: [QuadList] Weekend Mystery Pic  for 3/12/11


For this weekend's challenge, identify the function of this control and  
what  machine it is on.  As far as I know, it is the only control  of this 
design on any quad machine.
 

 
Don Norwood
Digitrak Communications, Inc.
_www.digitrakcom.com_ (http://www.digitrakcom.com/) 



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