[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: line timebase board

<< Can I ask the group whether, when powering up or powering down, a
 Rank Mk. III Digi 4, anyone has experienced a line timebase board going
 to 'heaven'( or Hell !! ) >>

The long and short answer is, yes.

The +70 volt supply in the Mk. III is unregulated, hence it tends to come up
faster on power-up, and hang around a little longer on power-down, than the
regulated 12-volt supplies that power the rest of the board. 9,999 times out
of 10,000 everything will be fine when you power up or down, but there will
be that one time when you catch it just right and pop the output transistor.
 Then the next time power is applied, all the usual stuff goes "blooey."

While it would be easy enough to mod the 70-volt supply so it goes on and off
with the 12-volt supplies, it seems that recent Cintel replacement line
timebase boards have better semiconductors and improved design compared to
the earlier versions, so they tend to hold up better than the originals did.
 If that's what you have, it might pay to buy a new replacement, then fix
your old one and keep it for a spare.

Christopher Bacon
DuArt Film & Video

thanks to Sam Dlugach, Dean Humphus, & Clark Bierbaum 
for support of the TIG in 1997
mailinglist digest available......posting guidelines on the webpage