[QuadList] Rebuilding RCA TR-600s - Success

[bill.spencer at northstarstudios.tv]

John,

 

There is also an air damper on the reel tension arms that needs to be
moving smoothly.

 

Bill Spencer

RF Engineering Supervisor

NorthStar Studios, Inc.

3201 Dickerson Pike

Nashville, TN 37207

 

Phone 615.650.6000 ext. 6610

Cell 615.445.5616

Fax 615.650.6027

email bill.spencer at northstarstudios.tv

 

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From: quadlist-bounces at quadvideotapegroup.com
[mailto:quadlist-bounces at quadvideotapegroup.com] On Behalf Of Rob
Lingelbach
Sent: Thursday, September 10, 2009 2:57 PM
To: Quad List
Subject: Re: [QuadList] Rebuilding RCA TR-600s - Success

 

 

On Sep 10, 2009, at 4:39 PM, John Walko wrote:





Rob:

 

When first starting the tape, the tension arms have some minor
oscillation, but once the tape locks up, they remain pretty much
centered. 

 

If I'm not mistaken, there's a feedback loop in lockup back to the arms
and it was my first experience with the whole idea of Phase Lock Loop.
(vague recall could be wrong)





The one issue I noticed is if the supply reel is full (just starting
playback) and the take up reel is empty, we have more tension issues.
Spot reels are a lot easier to work with. 

 

the less mass in consideration, the faster the feedback loop for lockup?


I remember with large reels and mass a lot of slewing, and then
sometimes 

the eventual drop of a loop and stop, but I don't think I ever broke a
tape on a 600.

 

Sometime it would be interesting to recall the Kafkaesque times when
after 12 hours of dubbing one would blow a hole in a master for which
there was no protection copy... 





We are trying to match reel sizes as closely as possible...but are
having trouble because we don't have a take up reel as large as a
one-hour supply reel.  We will need to get one.

 

and you're not even into the 90s yet :)

 

	

	We backed off slightly and are adjusting the tension to try to
keep the arms centered between the two stops.

 

there's an art to this, and there might have been some mods to introduce
wider tolerances to the PLL circuit(s)...

 

There was an engineer at Unitel, Rex Chookolingo, whom I might be able
to find who used to tune my TR600s.   He was on the TIG not long ago...


 

but I think there are also several already here who have the Knowledge.





 Regarding maximizing the RF envelope, the video just seems to look
better when running in manual.

 

sounds right.

 

 

--  

Rob Lingelbach

rob at colorist.org

 

 

 

 

 

 

 

 

 

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