[Frameworks] Seeking Projector Manual (Eiki EX-2000A)

[Steve Polta]

Ok ok.
This is fun.
But I'm really looking for info on the lamp's focusing knobs. Specifically
on the white plastic cover that covers the knob that controls how close/far
the lamp is to/from the lens/screen. Even more specifically I'm wondering
if the loss of this plastic cap (like for example if it melted due to heat)
is a big deal.

Asking for a manual was sort of a bonus (to myself/Cinematheque) because
once we had one, lent it, and didn't get it back.

Anyone plastic cap folks out there?

Steve

On Sep 18, 2017 7:22 PM, "Scott Dorsey" <kludge at panix.com> wrote:

> What's wrong with the xenon lamp circuitry?
>
> It should be a constant current source, combined with a little high voltage
> supply to strike the lamp.  When the high voltage pulse makes the thing arc
> over, the plasma between the contacts is conductive so all of a sudden the
> thing turns into a low resistance device and it only takes a couple hundred
> volts for the arc to be sustained.  The constant current source means that
> the thing remains at the correct operating point as the electrodes slowly
> burn away.
>
> I _think_ that the EX-2000A uses trick magnetics to do the job... it's a
> big saturable reactor that acts as an AC constant current source, then
> rectifiers to turn it into DC, and then a filter capacitor made with
> multiple capacitors and inductors in a chain to eliminate the ripple.
>
> You could talk to Steve Guttag, I know he has worked on those occasionally.
> There isn't much to fail non-catastrophically.
> --scott
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