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<DIV>I have followed the discussion of the solvents that folks use. I have
learned a great deal that I never knew.</DIV>
<DIV> </DIV>
<DIV>The GREEN tape was included sometimes on the first Ampex 1 inch
machines. The 7000 series. It was a burnishing tape used in head
replacement. I never used it as it would wear the heads very fast.</DIV>
<DIV> </DIV>
<DIV>I am wondering what the modifications were to the servos. I can not
see a mod to the Reference discriminator as the machine had to switch between
several sync sources in normal operations. Video in during record and
external during playback. If it were to go to external at all times,
during record the vertical sync placement on tape would not meet SMPTE
specifications or if asynchronous, it would float at all times making the tape
unplayable. The two rotary switches on the front of the servo would allow
you to override the normal operation and allow you to do this. </DIV>
<DIV> </DIV>
<DIV>The Capstan discriminator was touchy. If one put the 625 oscillator
control in parallel with the 525 control it became a fine frequency
control. In our machines the Capstan was critical for use on a machine
that was an editing machine. The servos had to be a close to perfect just
before the edit to prevent whips and glitches. It was an easy procedure that
resulted in never having a problem. Just set the discriminators and
oscillators before each session. It took about 2 minutes and the results
were very consistent. We also found the tach position was easy to set if
you used the demod out in pulse cross. We had some of he best edits in the
market. The only time we had a problem with tach phase was when an AVR 2
was used to record the edits and one frame edits were made. There was
something that caused a slight phase jump for about a field or two. It was
never out of the range for the TBC but just irked us.</DIV>
<DIV> </DIV>
<DIV>Chris Hill</DIV>
<DIV>WA8IGN</DIV></FONT></BODY></HTML>