[QuadList] TCR-100 (was 1" Machine glue)

[Don Norwood]

----- Original Message ----- 
From: "Dennis Degan" <DennyD1 at verizon.net>

On Feb 2, 2010, at 5:44 PM, Don Norwood wrote:

 > I never had more than a casual look at the TCR-100, and didn't 
realize that it used the same head as the other machines. Threading 
must have been quite a trick. How did they do that? 

I offer:

Unlike the Ampex machine's cartridges, RCA's carts could open in a way 
that exposed the tape at 3 sides.  Aluminum doors that wrapped around 
the cartridge would open, rotating on their spring-loaded hinges 90 
degrees.  This allowed a pair of pins to reach into the cart and pull 
the tape out.  The pins were each mounted on a machined polished track 
driven by a bicycle chain.  Each travelled a distance of about 2 feet 
diagonally in order to span the vertically-mounted width of the 
transport.  Though nowhere near as fast as the Ampex machine, the 
movement of those pins was fast enough to be dangerous if your hand was 
in the wrong place at the wrong time.
The entire assembly would then move horizontally to thread the tape 
across the erase, audio, quad video heads, capstan and guides, aided by 
guide blocks, which was followed by a slight retraction of the guide 
pins to avoid tape motion interference.  The action was reversed to 
return the tape loop back into the cartridge.

Dennis Degan, Video Editor-Consultant-Knowledge Bank
  NBC Today Show, New York

Hi Dennis:

The part I was unclear on was specifically the tape threading into the head assembly.  Ampex's retractable guide made it easy, but I had not thought about RCA using a standard head.  Were the guide blocks you mentioned attached to the head or to the TCR frame?  The Youtube video isn't quite good enough to see the detail.  I guess I need to go to Boston and see Paul's machine in action!

Don

Don Norwood
www.digitrakcom.com

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