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

Re: MK111c hair pulling problem

>The problem is as follows,when you set up on a open gate your pec
>levels(ie) just below clip level as if you were checking shading alignment
>and  stored that scene in a frame store then set up a split screen so as to
>compere the reference image with the live image.At this point levels begin
>to change either up or down on all three channels,this change is very
>subtle and could take 5 mins to change or 5 hours. <snip>
>Fergus Mc Carthy
>Windmill Lane

1. Is a card being used in the gate to prevent the cells from being
overloaded when film is not on the machine? This can cause drift as the
cells recover.
2. Are any of the supplies on the scan and signal stabilizer drifting as well?
(Probably not if the test is always okay).
3. Is the tube beam current drifting? 
4. Does the +150V supply drift?  
5. How old is the tube?
6. Some older machines had a problem with the rubber sleeving on the
infamous pink wire going slightly conductive over time.  This can manifest
itself as drift and many other strange problems. 
7. Does the machine have Accuglow, Festival, or standard Rank burn
correction. In some machines the original black shading cards can drift.
Does the shading or burn system influence the drift in any way?
8. Does the machine have Digital Deflection or a standard scan system?
Sometimes, with beam current or scan related drift, Digital Deflection can
make a difference. 
Craig Nichols
Todd-AO Video