[QuadList] RCA Headwheel

[trandoc at aol.com]

 Guy,

Yes, the main idea was for the TCR so the tape could be unthreaded quickly with the drum stopped. I remember playing with those pots to get the headwheel to stop without going in the opposite direction!

Harold

 


 

 

-----Original Message-----
From: Guy Spiller <quadruplex at verizon.net>
To: Quad List <quadlist at quadvideotapegroup.com>
Sent: Sat, Apr 17, 2010 5:21 pm
Subject: Re: [QuadList] RCA Headwheel


  Yes, it does, although the headwheel servo output is shut off if airpressure is below minimum.  The digital servo also quickly stops theheadwheel whenever the machine goes into "stop" mode for any reason. It reverses the phase of the motor voltage and has some tweaks in theservo to time the duration for optimum stopping effect with anyparticular headwheel assembly.
It might have saved a few heads from damage when unthreading a TR-70, but I suspect the circuit was probably designed to speed the cartchanging operation  in the TCR.
Guy

On 4/17/2010 6:59 PM, trandoc at aol.com wrote:
  
 Helloagain,
  
If my memory serves, the RCA digital servo had a brake circuit in theheadwheel motor driver that would stop the motor if air bearingpressure was lost.
  
Harold
  
  
 
  
  
 
  
  
 
  
  
-----OriginalMessage-----
From: Don Norwood <dwnorwood at embarqmail.com>
To: Quad List <quadlist at quadvideotapegroup.com>
Sent: Sat, Apr 17, 2010 7:57 am
Subject: Re: [QuadList] RCA Headwheel
  
  
  
Harold is correct if this is an air bearing head, and moreimportantly, it can be seriously damaged by turning it without air.
  
 
  
The nameplate will have an MI- number.  Give us that number andwe can tell if it is air or ball bearing, 5 or 10 mil.
  
 
  
Don
  
    
-----Original Message ----- 
    
From:    trandoc at aol.com 
    
To:    quadlist at quadvideotapegroup.com    
    
Sent:Saturday, April 17, 2010 5:03 AM
    
Subject:Re: [QuadList] RCA Headwheel
    

    
        
Scott,
    
The headwheel will not turn freely without a source of air pressure.Maybe someone on the list with an RCA machine could use it.
    
Regards,
Harold
    
    

    
    

    
    

    
    
-----OriginalMessage-----
From: Scott Thomas <scottgfx at mac.com>
To: Quad List <quadlist at quadvideotapegroup.com>
Sent: Sat, Apr 17, 2010 12:52 am
Subject: [QuadList] RCA Headwheel
    
    
    
I was talking to our CE today. I had sent him the VR-2000 videos that Park had 



put up recently. He then brought me over to the engineering closet and showed me 



something I hadn't seen in around 20 years; a case with an RCA headwheel 



assembly.







It looks fairly intact, but the motor doesn't spin freely. Probably too many 



years in the humid Florida weather. It had a sticker indicating that it had been 



refurbished by... (CVC??? I don't remember, the company owned by Kodak. I know I 



saw a lot of those labels before)







Is it just an artifact to be admired, or should I implore the company to have it 



refurbished for some greater good?







Anyway, it was fascinating to see one again.







Scott Thomas








    
    
    
  
  
  
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-- 
Guy Spiller
email: quadruplex at verizon.net
phone: (804) 379-2050
website: www.GuySpiller.com
Midlothian, VA
 
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