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Installment Five: "A Tour of the Marquee CRT Chassis: Service Menu & Alignments"
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The Utilities Menu was the subject of our Fourth installment (see PIC 1); Service is the ninth item in
Utilities but deserves a close and lengthy exploration. Half of all installation setup is done here and in
the alignment of the tube magnetics, and image quality can change drastically if the alignments are
poorly done. We want to perform service alignments on projectors that have had at least a sixty minute
warmup; some advise after retubing that 300 viewing hours be accrued before investing in an ISF-caliber
fussy setup. The Service Menu is passcode protected and is accessed by pressing UTIL, 9, 0901 on the
Marquee remote (see PIC 2):
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UTIL, 1 Source Setup (see PIC 2)
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| Service,1 |
Color Temperatures
(see PIC 3) The technician can set Drive levels
and G2 levels for user presets of 3200K, 6500K or
9300K. Color Temperature deals with how a scene
would look if lluminated with a tungsten bar heated
to incandescence as the only light source. 3200K
would have a rather orange look, 6500K has been
likened to the quality of sunshine on a cloudy day,
and 9300K has a bluish tinge; the hotter our tungsten
source gets, the more towards blue it goes. In the
absence of costly colorimeter test equipment we
can adjust Color Temperature, a.k.a. Gray Scale,
in the following manner. Set user Contrast and Brightness
controls at 50, and feed the projector a signal
of 31khz scan or higher. Enter the Service Menu
and select 6500K. Use the # key on the keypad to
display the pattern of various intensity blocks,
called the Stairstep pattern for how the blocks
(see PIC 4) appear on an oscilloscope (see PIC 5).
For the red stairstep we want to set background,
or G2 level, so that the second darkest block is
just visible without making the darkest block visible
(a beginning Drive setting of 35 is advised). If
G2 is too low, blocks that should be visible are
lost, the tube does not turn on to reproduce deepest
grays, andpicture detail may be lost (see PIC 6)
If correctly set, the second block is just visible
(see PIC 7), if G2 is too high then what should be true black
is elevated into gray and is not faithful to the
program material (see PIC 8). To align green we
push the Enter key and a green stairstep should
appear. With a Drive setting of 90, set the Green
G2 so the second darkest block is just visible (see
PIC 9). Push Enter, and the blue stairstep is displayed.
With blue Drive at 50, set the G2 so that the second
darkest block is just visible. Push Enter, and stairstep
for all three colors is displayed. If the brightest
blocks do not produce good white then the Drive
level for the color that is too high or too low may need to be adjusted;
if the technician now presses the Tint key he can
adjust red, green or blue Drives and G2s while all
three colors are displayed (see PICs 10, 11, 12).
Be aware that Drive and G2 do interact some; after
setting Drives go back and reconfirm that for each
color, the second darkest block of stairstep is
just visible. For those not confident that they
can do these alignments it is recommended to note
the starting values on paper so they can be reentered as defaults if the desired results
are not enjoyed. We also advise setting all Zone
Contrast values to 50 for the edges and corners
before setting Color Temps; Zone Contrast is found
in Service, 1, 5; push "0" to null all
Zones. To set 3200K or 9300K one may either reduce
blue levels for 3200K compared to values for 6500K,
and raise blue levels for 9300K compared to 6500K,
or bring in someone with a color analyzer for the
most accurate setup. Some advise removal of the
contrast modulation board as unnecessary for home
use.
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| Service, 2 |
Zone Focus These alignments (see PIC 13) are for beam focus
or spot size at multiple points on each tube face; we advise
first setting user focus to 50 by pushing PIC, 4 on the keypad.
Since correct stigmation correction affects focus
everywhere in the raster, stig alignment is best
done first;; flare magnet and raster centering also.
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Service, 3
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Red/Blue Height
Here the technician can match red and blue raster heights
to green so as to place the least load on the dynamic
convergence section, which helps convergence stability.
This alignment is always required after changing resistors
for the anamorphic mod. See Marquee Anamorphic Mod in the
Tech Tips section for more info.
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Service, 4
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Reinitialize
The technician can select from several modes (see PIC 14)
that will reset all parameters to defaults. A complete reset
is advised when beginning a new installation, to clear out
all old unwanted settings. A reset can not reach all levels
of memory; some settings such as serial number, model number,
runtime hours, and color temp parameters are beyond reach
of resets, and are stored in a chip on the backplane so
they stay with a chassis even if a control module gets replaced.
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Service, 5
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Status Page Message
The technician can enter a text message, such as the name and
phone number for technical support; the message will be
displayed as part of the status page when * is pressed.
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Service, 6
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Diagnostics
The technician can read out hardware and software versions, viewing and
standby hours, and last key pressed infomation useful in troubleshooting
a control system. (see PIC 15).
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Service, 7
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Stigmation Correction
Here the technician can adjust dot shape (see PIC 16) at nine
zones of the raster for each color. A round dot out in the corners
will permit tighter focus than an oval dot. Zone stig is a standard
feature on the 8500, 8500LC, 9000LC, and 9500LC, Ultras too. The
feature requires a stig waveform generator mounted on the control
board, a stig amplifier board mounted on the rear heat sink, and a
version of the focus yoke which includes stig coils inside it. To
adjust stig correctly, input a non-interlaced signal of about 31khz,
or select 31khz from Internal Frequencies (push UTIL, 1, 6, 2). Push
the # key for dots only pattern, take user focus to 90, and raise
contrast to 80+ until dot shape is clearly visible. Enter the stig
adjust routine by keying in UTIL, 9, 0901, 7, then adjust North/South
and East/West dot shape with the arrow keys until the red dots in the
center are round. Continue through the routine by pressing ENTER until
all zones of red, green and blue are correctly set. You may back up
in the routine by pressing the * key at any time, and when completed
you can save or discard the changes in the adjustments if necessary.
Stig is global through all memories and need only be aligned the first time.
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Service, 8
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Delete any unlocked Input or Recall memory here.
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Service, 9
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Service, 0
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This is the double secret protected Manufacturer's Menu (see PIC 17),
where the factory technicians can enter Marquee or Vision or Madrigal
as the brand, 8500, 9500LC, Vision One, Vision Two, MP8 or MP9, the
serial number (all these for the * OSD) as well as timing values
for focus at different scan rates. We cannot divulge the passcode
to this section, sorry!
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Our Marquee Chassis Tour will be continued in the next installment.
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Tim at E-Tech Systems Phoenix |
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