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<div> <font size="2"><font face="Arial, Helvetica, sans-serif">Guy,<br>
<br>
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!<br>
<br>
Harold<br>
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<div style="font-family: arial,helvetica; font-size: 10pt; color: black;">-----Original Message-----<br>
From: Guy Spiller <quadruplex@verizon.net><br>
To: Quad List <quadlist@quadvideotapegroup.com><br>
Sent: Sat, Apr 17, 2010 5:21 pm<br>
Subject: Re: [QuadList] RCA Headwheel<br>
<br>
<div id="AOLMsgPart_3_90d55350-2005-4406-87e8-eca242fd2db8">
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.<br>
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.<br>
Guy<br>
<br>
On 4/17/2010 6:59 PM, <a class="moz-txt-link-abbreviated" href="mailto:trandoc@aol.com">trandoc@aol.com</a> wrote:
<blockquote type="cite"><font color="black" face="arial" size="2">
<div> <font size="2"><font face="Arial, Helvetica, sans-serif">Hello
again,<br>
<br>
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.<br>
<br>
Harold<br>
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<div style="font-family: arial,helvetica; font-size: 10pt; color: black;">-----Original
Message-----<br>
From: Don Norwood <a class="moz-txt-link-rfc2396E" href="mailto:dwnorwood@embarqmail.com"><dwnorwood@embarqmail.com></a><br>
To: Quad List <a class="moz-txt-link-rfc2396E" href="mailto:quadlist@quadvideotapegroup.com"><quadlist@quadvideotapegroup.com></a><br>
Sent: Sat, Apr 17, 2010 7:57 am<br>
Subject: Re: [QuadList] RCA Headwheel<br>
<br>
<div id="AOLMsgPart_3_027e1a85-40be-424e-8072-1e30f6facb00">
<div>Harold is correct if this is an air bearing head, and more
importantly, it can be seriously damaged by turning it without air.</div>
<div> </div>
<div>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.</div>
<div> </div>
<div>Don</div>
<blockquote style="border-left: 2px solid rgb(0, 0, 0); padding-left: 5px; padding-right: 0px; margin-left: 5px; margin-right: 0px;">
<div style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;">-----
Original Message ----- </div>
<div style="background: rgb(228, 228, 228) none repeat scroll 0% 0%; font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal; -moz-background-clip: border; -moz-background-origin: padding; -moz-background-inline-policy: continuous;"><b>From:</b>
<a title="trandoc@aol.com" href="mailto:trandoc@aol.com">trandoc@aol.com</a> </div>
<div style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;"><b>To:</b>
<a title="quadlist@quadvideotapegroup.com" href="mailto:quadlist@quadvideotapegroup.com">quadlist@quadvideotapegroup.com</a>
</div>
<div style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;"><b>Sent:</b>
Saturday, April 17, 2010 5:03 AM</div>
<div style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;"><b>Subject:</b>
Re: [QuadList] RCA Headwheel</div>
<div><br>
</div>
<font color="black" face="arial" size="2">
<div><font size="2"><font face="Arial, Helvetica, sans-serif">Scott,<br>
<br>
The headwheel will not turn freely without a source of air pressure.
Maybe someone on the list with an RCA machine could use it.<br>
<br>
Regards,<br>
Harold<br>
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<div style="font-family: arial,helvetica; color: black; font-size: 10pt;">-----Original
Message-----<br>
From: Scott Thomas <<a href="mailto:scottgfx@mac.com">scottgfx@mac.com</a>><br>
To: Quad List <<a href="mailto:quadlist@quadvideotapegroup.com">quadlist@quadvideotapegroup.com</a>><br>
Sent: Sat, Apr 17, 2010 12:52 am<br>
Subject: [QuadList] RCA Headwheel<br>
<br>
<div style="margin: 0px; background-color: rgb(255, 255, 255); font-family: Tahoma,Verdana,Arial,Sans-Serif; color: rgb(0, 0, 0); font-size: 12px;" id="AOLMsgPart_0_1c1b59a1-3d7e-4f58-b23d-cc39d53510a1">
<pre style="font-size: 9pt;"><tt>I was talking to our CE today. I had sent him the VR-2000 videos that Park had <br>
<br>
<br>
<br>
put up recently. He then brought me over to the engineering closet and showed me <br>
<br>
<br>
<br>
something I hadn't seen in around 20 years; a case with an RCA headwheel <br>
<br>
<br>
<br>
assembly.<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
It looks fairly intact, but the motor doesn't spin freely. Probably too many <br>
<br>
<br>
<br>
years in the humid Florida weather. It had a sticker indicating that it had been <br>
<br>
<br>
<br>
refurbished by... (CVC??? I don't remember, the company owned by Kodak. I know I <br>
<br>
<br>
<br>
saw a lot of those labels before)<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
Is it just an artifact to be admired, or should I implore the company to have it <br>
<br>
<br>
<br>
refurbished for some greater good?<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
Anyway, it was fascinating to see one again.<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
Scott Thomas<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</tt></pre>
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<br>
<pre class="moz-signature" cols="72">-- <br>
Guy Spiller<br>
email: <a class="moz-txt-link-abbreviated" href="mailto:quadruplex@verizon.net">quadruplex@verizon.net</a><br>
phone: (804) 379-2050<br>
website: <a class="moz-txt-link-abbreviated" target="_blank" href="http://www.GuySpiller.com">www.GuySpiller.com</a><br>
Midlothian, VA</pre>
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<pre style="font-size: 9pt;"><tt>_______________________________________________<br>
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