[QuadList] AVR 3 heads question

lee williams lasvegastvengineer at yahoo.com
Tue Aug 2 11:01:59 CDT 2011


Hello Tony, 
Please review the original question. 

All NEW heads ( have gone through 4 in the last 2 years) will not play the old tape stock. 
Only 1 very old head (that is now wearing out) will make a clean picture. 

I know ( guess) the stock was not recorded properly, but what ever is off on the recordings is constant. 

Is there a way to reproduce what ever is tweaked on that odd ball head because my client has a couple of thousand tapes that this head was the only thing that would play them? 

Thanks 
Lee 

--- On Tue, 8/2/11, Videomagnetics <vmi at csprings.com> wrote:

From: Videomagnetics <vmi at csprings.com>
Subject: Re: [QuadList] AVR 3 heads question
To: "Quad List" <quadlist at quadvideotapegroup.com>
Date: Tuesday, August 2, 2011, 8:35 AM



 
Lee,
This could be a rotary transformer problem on the head.
 
Tony

  ----- Original Message ----- 
  From: 
  Chill315 at aol.com 
  
  To: quadlist at quadvideotapegroup.com 
  
  Sent: Monday, August 01, 2011 3:13 
  PM
  Subject: Re: [QuadList] AVR 3 heads 
  question
  

  Lee
   
  What does the Demod out look like?
   
  Chris Hill
   
  
  In a message dated 8/1/2011 5:12:28 P.M. Eastern Daylight Time, lasvegastvengineer at yahoo.com 
  writes:
  
    
      
      
        
          Hello Larry, 
           
          Sorry but not the problem, 
           
          The closest thing I can describe the effect is white streaks with 
          analog snow in them trailing out like a comet tail from the trailing 
          edge of anything white in the picture. 
           
          No digital blocks, Not a head clog. 

          Thanks. 
           
          Lee 
           
          
--- On Sun, 7/31/11, LARRY 
          <leodham at centurylink.net> wrote:

          
From: 
            LARRY <leodham at centurylink.net>
Subject: Re: [QuadList] 
            AVR 3 heads question
To: "Quad List" 
            <quadlist at quadvideotapegroup.com>
Date: Sunday, July 31, 
            2011, 6:58 AM


            
            #yiv1220734295  P {
MARGIN:0px;}


            
            Hello Lee,
             
            I have been following some of the back-and-fourth e-mails on 
            your tape playback trouble.
            Here is my two cents worth:
             
             I have experienced this problem before.
            The video is tearing in what looks to be square blocks? 
            right??
            I have encountered that very same effect here on a VR-1200b. It 
            was caused here by the playback equalization. A good way to verify 
            if this is the problem is to go to manual equalization, and turn 
            down(reduce) the EQ one channel at a time. If you see an 
            improvement, then stop the machine, unthread the tape, and look with 
            a magnifier at the drum surface behind each head tip(trailing 
            surface). You may find a small build-up of black-looking stuff 
            behind one, or all, of the head tips on the drum edge surface 
            itself. 
            This build-up increases the diameter of the head drum just 
            enough to decrease tip penetration at the head.
            Usual cleaning of the tips will not remove this buildup. 
            Alcohol and a fingernail will. CAREFULLY!!
             
             OK, hope this helps,
            larry
----- Original Message -----
From: "lee williams" 
            <lasvegastvengineer at yahoo.com>
To: "Quad List" 
            <quadlist at quadvideotapegroup.com>
Sent: Sunday, July 31, 
            2011 12:24:33 AM
Subject: Re: [QuadList] AVR 3 heads 
            question


            
              
              
                
                  Hello, 
                  Answers below questions. 
                   
                  

--- On Sat, 7/30/11, Chill315 at aol.com 
                  <Chill315 at aol.com> wrote:

                  
From: 
                    Chill315 at aol.com <Chill315 at aol.com>
Subject: Re: 
                    [QuadList] AVR 3 heads question
To: 
                    quadlist at quadvideotapegroup.com
Date: Saturday, July 30, 
                    2011, 9:38 AM


                    
                    Lee
                     
                    How does the RF envelope look on the scope?
                    No Scope - I can tell I have plenty of RF with my 
                    tracking adjustment. 
                     
                     
                    How is Vertical lining up with house?
                    AVR3 is on internal generator. No difference if I hook 
                    up a black source to the machines. 
                     
                     
                    Do you have an alignment tape?  If so, how does it 
                    play and where is the tracking knob?
                    Alignment and known good tapes play fine. 
                    Client has several thousand tapes made in the early 
                    80's (probably on a VR2000) 
                     
                    Are you using manual or auto tracking?
                    Manual normally.  No difference in auto. 
                     
                    30 lines of black may be that you are one or two head 
                    passes off in the vertical realm.  The tearing may be 
                    due to the fact that you can not get the head centered on 
                    the track perfectly.  
                     
                    The head assemblies are made so good that they meet 
                    SMPTE specifications with in a few hairs.  This is to 
                    create interchangeability between machines.  
                     
                    I would not touch the heads in any way as you will 
                    destroy the interchange.  It is a critical 
                    factor.  If you saw the recent slide show on here, you 
                    see the great deal of care taken to make a head.
                     
                    Now the tape you have may have been done in a non 
                    standard method.  That is why all the questions.  
                    
                     
                    I always assume that the tape was poorly made.  
                    Many operations did not do best practices and thus there is 
                    a lot of poorly made tapes.  
                     
                    I know it's the tape that is off. (several thousand of 
                    them) 
                    Now how do I get them transferred short of sending in 
                    the weak head to the rebuilder and have him duplicate the 
                    deviation were the head is off of true? 
                     
                    Chris Hill
                    WA8IGN
                     
                    
                    In a message dated 7/30/2011 11:56:38 A.M. Eastern 
                    Daylight Time, lasvegastvengineer at yahoo.com writes:
                    
                      
                        
                        
                          
Hay all, 
Have a good one here 
                            ??? 

AVR3 Mark XV heads. 

Have some 2" 
                            tape that when you try to pull it through the 
                            machine will will give you something that looks like 
                            video tearing in the whites and slow horizontal 
                            jitter. 

If I slam the tracking all the way 
                            down, I get a very clean picture, but about 30 lines 
                            of black overhead on the screen. 

I see this 
                            on all my new(er) heads I get from both Aheadtek and 
                            VideoMagnetics. 

I have 1 very warn out head 
                            (supplier unknown) that will lock to these 
                            tapes

Has anybody seen this before and is 
                            there a way this heads set up can be duplicated? 
                            

Thanks 

Lee 
                      



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