I used to work with the VO-2800 & VO-2850 used for broadcasting in USAF AFRTS-Stations in the late 70'ies. It was a 'Pain-in-the-xxx' to keep them going. Pinch-rollers died about twice a month!
The 2850 was VERY sensitive to fluctuations of 110V/60cps. Just a short 58,5cps hick-up would make the Timebase corrector skip frames. The 2850 was modified to be driven 1,5 line ahead of the main sync by the TBC, about what the TBC would correct in those days. When the generators at the USAF-base (4684th ABGp) reacted to some surge they would slow down to about 58,5cps for a split second, enough for the 2850 to take a spin. I actually had to build a PLL-circuit with temperature compensation and all, make a running print covering about 48 hours, just to prove the machines were in 'perfect' working condition.
Can you believe, after 25+ years, this nightmare still hunts me?
Submitted Mon, 11 Sep 2006 17:04