[QuadList] RCA Headwheel

[Guy Spiller]

Yes, it does, although the headwheel servo output is shut off if air 
pressure is below minimum.  The digital servo also quickly stops the 
headwheel whenever the machine goes into "stop" mode for any reason.  It 
reverses the phase of the motor voltage and has some tweaks in the servo 
to time the duration for optimum stopping effect with any particular 
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 cart 
changing operation  in the TCR.
Guy

On 4/17/2010 6:59 PM, trandoc at aol.com wrote:
> Hello again,
>
> If my memory serves, the RCA digital servo had a brake circuit in the 
> headwheel motor driver that would stop the motor if air bearing 
> pressure was lost.
>
> Harold
>
>
>
> -----Original Message-----
> 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 more 
> importantly, it can be seriously damaged by turning it without air.
> The nameplate will have an MI- number.  Give us that number and we can 
> tell if it is air or ball bearing, 5 or 10 mil.
> Don
>
>     ----- Original Message -----
>     *From:* trandoc at aol.com <mailto:trandoc at aol.com>
>     *To:* quadlist at quadvideotapegroup.com
>     <mailto: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
>
>
>
>     -----Original Message-----
>     From: Scott Thomas <scottgfx at mac.com <mailto:scottgfx at mac.com>>
>     To: Quad List <quadlist at quadvideotapegroup.com
>     <mailto: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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