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Reply to: RE>Sparkles---------------------
Some interesting clues, but are you sure there's a correlation
to all the various Rank modes?
Most of the random white flashes we get (aside from plain old
memory/addressing fubars) is due to static discharge. It is
quite possible that you have air ionizers and/or ionized air
knives on the Rank which are causing this. This (or similar
discharge) theory is supported by the fact that increasing the
RH% seems to help. Try turning off your ionized air just for grins.
If that fixes it, try larger resistors in the Hipot feed, and
check the outflow orifices where the ionization fingers are to
make sure they are not crudded with stuff that may leak the charge.
Also, it's a good idea to keep the humidity up anyway, so keep
doing that. It's winter, so this problem will be at its worst,
especially in winter climates, like north of the Mason-Dixon
line. Here in NYC, we see this type of thing come and go with
Another track to investigate is some discharge in your mains.
perhaps a faulty wire or connector in your plant AC wiring is
arcing over at sine wave peaks. That might explain the banding
and the correlation between 24 and 30 fps speeds. Does not explain
the other factors, like run-still difference. This stuff can be
tracked with "sniffers". You can try thos cable tracker devices
like "Fox & Hound" and touch around the outlet plates in various
Good luck. -bt
Date: 01-26-96 7:36
To: Topazio, Bill
From: JimErkson at aol.com
I've been having problems with "sparkles" on a Mk III, Digi IV Rank for some
time now. Rather than go over the dozens of things that have been attempted
to relieve the problem, let me just say that the problem seems to be related
to static discharge; either of the film or something else, and that the only
thing that's been tried that has partially relieved the problem has been to
increase the humidity in the Rank area to around 55%.
The sparkles have the following characteristics:
1) They are one field in duration, followed by a clean field, followed by
another one field duration of the same sparkle in the same position.
2) They are colorless, white, and exceedingly small.
3) They all appear in the upper 1/3 of the picture area, within a horizontal
band approx 30 - 40 lines wide.
4) They are more numerous when running 30 fps versus 24 fps
5) They are far more numerous and elongated, horizontally, when running
6) They never appear when the transport is still.