[QuadList] AVR 3 heads question

Mon Aug 1 16:13:23 CDT 2011

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

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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