The following procedure was written by Curt Palme.
When you buy a rebuilt tube from
VDC, the tube needs to be
conditioned. It’s also a good idea to do this when you buy a new tube, but my
understanding is that Sony and Panasonic already do this. It can’t hurt to do it
A tube needs to be conditioned as the phosphor has not properly cured when
it’s sprayed on the tube. If you start using the rebuilt tube without hardening
the phosphor, premature browning of the phosphor will occur in as low as 200
hours. What’s needed is an all white field put on the face of the tube which
will raise the temperature of the phosphor and it will harden so it can be used
normally without discoloration.
Here are the steps to successfully condition a tube:
Note: Be aware that this is a slow process and requires 4 days
(96 hours) to complete correctly. Shortcuts are not possible here!
1) Set your system up so that a DVD signal is running into the projector with
at least a 480p resolution. You don’t want to use 480i, as the scanning lines
will be too obvious on the face of the tube, and can wear into the face of the
tube during the conditioning process. You want to run at least 480p or line
2) If you don’t already have this, you’ll need an AVIA test DVD that can
display an all white pattern (100IRE) or a PC with an all-white screen test
pattern (make sure to turn off your screensaver!).
3) Max out your height and width to 100% or maximum within the menus or
controls in your projector. If your raster now spills over the edge of the tube,
you’ll be fine, you won’t be driving the tube very hard during the conditioning.
4) Electronically defocus the tube, so that the image on the face of the tube
is defocused as much as possible. (this is important, you need to defocus the
tube electronically, optical defocusing of the image on the screen will not work
for you) Run the focus control of the set to min or max, whatever defocused the
tube the most. Put on sunglasses and look directly into the tube to make sure
that the image on the face of the tube is now blurry.
5) Select the AVIA disc to produce an all white screen (100IRE) and make sure
that the 100 IRE message on the screen is disabled (turn off the subtitles), or
you’ll burn a fuzzy ‘100 IRE’ into the phosphor.
You should now have an all white image displayed on your screen. Freeze frame
this screen or use the A-B loop function so that this all white screen remains
on the screen. If you have only replaced a tube or two, you can disconnect the
applicable R G or B signal to the tubes that you have not replaced, no sense in
lighting up the tube face of tubes that work fine.
6) Turn the brightness and contrast down to 30% each. Run the all white field
like this for a full 24 hours, then bump up the contrast and brightness by 5%
each every 12 hours after that. Keep increasing the brightness and contrast by
5% until you get to 60% brightness and 60% contrast.
7) The Tube Conditioning is now done. Reduce the height and width back to
normal, reset the focusing of the set to normal, reconnect any R G or B cables
that you took off to disable them, and enjoy your new tube(s). Do a color
calibration if required. That’s it!
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