[QuadList] Servo Modes

[chill315 at aol.com]

That is a very difficult thing to do.  Boost is on for almost that long.  Then capstan has to frame before it can try to horizontal lock.  So what is your secret?

Have you changed boost?
Or is it on certain size reels?
Have you got a really good capstan roller?

I was able to get 3 second lock most of the time.  At 4 seconds it was time to tune the servos. 

Chris Hill

On Aug 23, 2012, at 12:26 PM, "C. Park Seward" <park at videopark.com> wrote:

> 
> I can get my 1200s to lock up almost instantly. It usually requires tweaking the servos for that particular tape. But most any tape will lock in two seconds or less.
> 
> Best,
> Park
> 
> C. Park Seward
> Cell: 818-535-2747
> Home: 541-476-6657
> 2" Quad and 1" "C" transfers
> The Transfer Lab at Video Park
> Visit us: http://www.videopark.com
> 
> 
> 
> On Aug 23, 2012, at 5:21 AM, Norman Hurst wrote:
> 
>> 
>> In the 1970s, my father led an Advanced Development group at RCA Broadcast and one of their projects was to improve the lockup time for VTRs.  Using a TR-70C, they developed a way to achieve lockup within a time measured in frames, not seconds:
>>   
>>   http://us.mg4.mail.yahoo.com/neo/launch?.rand=229377417&clmigstart=20110815
>> 
>> It worked by applying an acceleration profile such that when the tape reached the correct speed, it was also in phase with house sync.  I remember that to demonstrate it they had to manually hold the pinch roller against the capstan and keep the electronics in E-E until playback was locked.
>> 
>> The group was in the Terminal Equipment group, not in the VTR group.  When they demoed the system to the VTR group, it got the "NIH" reception: Not Invented Here.  It never made it into any product.
>> 
>> From: Don Norwood <dwnorwood at embarqmail.com>
>> To: Quad List <quadlist at quadvideotapegroup.com> 
>> Sent: Tuesday, August 21, 2012 2:38 PM
>> Subject: Re: [QuadList] Servo Modes
>> 
>> 
>> 
>> Hi Chris:
>>  
>> I have a VR-1200 that has a mod so that in H-lock mode, it functions exactly as you have described for the RCA LineLock.  It's a small circuit board added in the control panel.  Basically an NE555 timer controlling mode selection when Play is activated and the servo selector is set for H-lock mode. 
>>  
>> Don Norwood
>> Digitrak Communications, Inc.
>> www.digitrakcom.com  
>>  
>> ----- Original Message -----
>> From: Chill315 at aol.com
>>  
>> RCA offered four modes of lock, Pixlock, LineLock, Switchlock, and TW or Tone Wheel.
>>  
>> Pixlock was the same as Automatic in the Ampex Machines.  Linelock starts in full automatic and then after lock reverts to the same as Horizontal, Switchlock was vertical lock, and TW is the original servo system.
>>  
>> RCA did have the advantage with LineLock that it would always lock vertically for a clean switch and then if there was a problem, have a fast servo recovery.
>>  
>> 
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