[QuadList] Rebuilding RCA TR-600s - Success

Fri Sep 11 08:22:20 CDT 2009

John,

They are sort of self lubricating in that the piston is graphite based.
All I have ever done is clean the glass tube and look for wear.  If some
gunk from compressed dust bunnies, etc. gets in there they can not move
as smooth as they should and cause some bumps on the reels coming up to
speed.

There are also some electronic adjustments for reel tension and I have
found that the instructions in the manual are a good starting point, but
you sort of have to cheat for each machine to compensate for various
wear factors in the loop.  I try to make my adjustments with an hour
reel of tape wound half and half (or in the middle if you prefer) so the
loads are balanced between supply and takeup.  I don't have my Tentel
tension gauge any more so it is more just what looks right to my eye.
Another thing that is affected by the reel tensions is the rewind and
fast forward speed when winding tape.  To get mine playing good in
normal run the rewind is kind of slow, but I usually just run it off and
rewind on the Recortec cleaner.  It saves a little wear also on all the
fixed guides!

Sounds like you are doing great on your project.

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 John Walko
Sent: Friday, September 11, 2009 8:07 AM
To: 'Quad List'
Subject: Re: [QuadList] Rebuilding RCA TR-600s - Success

Bill:

I know about the air dampers you are talking about.  I have two spares,
plus the ones on each of the two machines.

Is there any way to service these?  Can they be lubricated (I doubt
it...I don't know what you would lube them with) or should they just be
cleaned if they are not operating smoothly.

Last I check they were working smoothly, but I haven't checked them in
awhile.

John

From: quadlist-bounces at quadvideotapegroup.com
[mailto:quadlist-bounces at quadvideotapegroup.com] On Behalf Of
bill.spencer at northstarstudios.tv
Sent: Thursday, September 10, 2009 6:08 PM
To: quadlist at quadvideotapegroup.com
Subject: Re: [QuadList] Rebuilding RCA TR-600s - Success

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

CONFIDENTIALITY NOTICE/HIPAA PRIVACY RULE: This message may contain
information that is privileged, confidential and exempt from disclosure
under applicable law. If you are not the intended recipient (or
authorized to act on behalf of the intended recipient) of this message,
please do not disclose, forward, distribute, copy, or use this message
or its contents. If you have received this communication in error,
please notify us immediately by return e-mail and delete the original
message from your e-mail system. Thank you.

________________________________

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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