[QuadList] Servo Lock Modes for RCA TR600

[Chill315 at aol.com]

Depending on the machine, the start up mode is the first mode.  It is  a 
short term mode to just get the head spinning.  We never see it in  
operations.  It is what I call the hidden mode.  Because the head is  at rest, there 
has to be a way to start it.  Once spinning, then we go into  all the rest of 
the modes.
 
For review, here are the modes in an RCA machine.  
 
First is Tone Wheel.
 
This is the most basic mode.  No H or V lock.
 
Next is switch lock.
 
This is the next step and by controlling the capstan so that it moves the  
tape to allow the track with Vertical Sync to be played back in coincidence 
with  house.  This mode is used in the editing process on the record  
machine.
 
Next is to find H lock.  
 
This aligns the H sync with house.  The control has to be much  tighter.  
Within a micro sec or so as the window of the TBC is so  small.
 
Line Lock is the same as H Lock with out finding vertical first.
 
I hated it when an operator put the machine in this mode and the on air  
switch jumped in MCR.  Plus you could not do crawls or IDs over the  tape.  
 
Hope that helped.
 
Chris Hill
 
 
In a message dated 11/15/2013 9:07:39 A.M. Eastern Standard Time,  
fkovach at sbcglobal.net writes:





I learned through a discussion with Chris Hill that  there are four, and 
possibly five types of servo lock for this VTR:
1. Tone  wheel lock
2. Switch lock
3. Pix lock
4. Line lock 
And a possible  #5. Whatever mode or combo of modes used in starting the 
tape up.  

Another theory question is the explanation of the "outer loop" and  "inner 
loop" circuitry used in this machine for the servos. 

Thanks for  any help you can give,
Fred 
 
Fred  Kovach 
Broadcast  Technician 
417-848-8381



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