[QuadList] Rebuilding RCA TR-600s

[John Walko]

Chris:

 

Thanks for the insight.especially about the reel motors.  I'm not sure it is
the solenoid.but it sounds like that is what is buzzing.replacing the
solenoid seems pretty straight-forward, if that is what it is.  It is the
solenoid that appears to actuate the reel brakes.

 

Regarding being in HB or LB, we did look at that switch.  In fact, we played
a low band tape and noticed that putting the switch into low band improved
the images (made it brighter and it appeared sharper.but that could be
imagined because it was brighter).  We were definitely in HB when attempting
to play the color tape.

 

I like the idea about the scope and testing the signal.will try that later.

 

Thanks;

 

John Walko

 

 

From: quadlist-bounces at quadvideotapegroup.com
[mailto:quadlist-bounces at quadvideotapegroup.com] On Behalf Of
Chill315 at aol.com
Sent: Tuesday, September 08, 2009 12:37 PM
To: quadlist at quadvideotapegroup.com
Subject: Re: [QuadList] Rebuilding RCA TR-600s

 

A couple of notes as to what to look for to solve your issues.  I have not
worked on this machine but the symptoms are universal.

 

The following is all speculation and conjecture.  Do not take it for gospel.
All legal statements etc. according to my Marx Brother Lawyers.

 

First, the seeing of two syncs and bursts.  This is due to the timing
difference between the machine and the house sync that you are using.  The
house sync is being inserted back in according to what you said earlier.
All that needs to solve this is to find out how to get the H phase to align
with the house sync.  If you are in Regen mode, this will disappear. 

 

The issue with the color bars changing color in the regen mode tells me that
the machine is not gen-locking to the incoming black burst in that mode.  A
way to tell this is to trigger your scope from the outside house burst and
look at the output of the machine.  If the two signals are moving, then you
are not locked.  

 

You should do this to get the machine to be in time with the external black.
Show house burst on one channel of the scope and the output on the other.
Then triggering off the house, get the two signals to line up.

 

Reel tensions have to be done quickly.  Do not remove the reel motors as
there is a possibility of issues.  The reel turntable heights are set to
SMPTE standards and not knowing how RCA did it you may have a minor issue.
Ampex did it by putting shims under each bolt for the reel motor.  These are
very specific to each one so if you change, then it requires a way to get
the height back to normal.  Possibly you could set up a measurement system
to note the height of the table above the deck at all four bolt holes and
then replicate the numbers when the motor is replaced.  I have never had a
motor go bad in over 20 years.  The only time that I had to remove a motor
was when someone slammed a reel on and broke the pin that holds the
turntable to the shaft.  I was lucky that the Ampex person that built the
deck had marked the shim sizes on the back of the deck.

 

The issue of the black and white tape looking good and then the color tape
going bad is interesting.  I do not know if the machine plays all three
standards.  If so was the switch in the correct position?  Or does it auto
switch like the TR-70?  If the latter, then look at that circuitry.  The
auto EQ does not have a burst in low band black and white so is shut off.
Manual adjustment is required and it is sometimes not that easy to see the
banding in black and white.  Play back color bars and see if the auto EQ is
working.  If not, do the manual adjustments to get the picture looking
right.  Then try the auto. It may be so far out that it can not adjust.

 

The long lock up would also be an indication of the fact that the machine
may be in the wrong standard.

 

Hope that helps.

 

Chris Hill

 

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