Hughes Model 230 Projector Service Manual

Chapter 2---System Description
Model 230 Service Manual2-59
2.3.11 Backplane PCB
The Backplane PCB is the interface that connects the Power Supplies, VICs,
PCBs, and other components together, either through a direct connection to a
connector on the Backplane or through cables to connectors on the Backplane
PCB. Signals are not modified in any way by the Backplane. It serves only as an
interconnecting point. Refer to Figure 2-17 for a general idea of how the
projector wiring is interconnected through the...

Chapter 2---System Description
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Chapter 3---Service Adjustments
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3.0  Service Adjustments
Contents
3.1   Arc Lamp Adjustment ............................................................................. 3-3
3.1.1   Arc Lamp Current Adjustment ....................................................... 3-3
3.1.2   Arc Lamp Alignment ...................................................................... 3-5
3.2 Electronic Module Tilt-up .............................................................................

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Figure 3-1.   Major components of the Model 230 Projector. 

Chapter 3---Service Adjustments
Model 230 Service Manual3-3
Figure 3-2.   View of CRTs, Relay lenses and 
ILA® Assemblies.
3.1   Arc Lamp Adjustment
An Arc Lamp adjustment must be performed whenever an Arc Lamp is replaced
and 
may be needed if the projector is heavily jarred during shipment. The Arc
Lamp Adjustment consists of 3 separate adjustment procedures; Arc Lamp
Current adjustment, Arc Lamp Alignment, and Condensing Lens X/Y positioning
adjustment. The Condensing Lens adjustment is not normally...

Chapter 3 Service Adjustments
3-4Model 230 Service Manual
 
 Figure 3-3.   Arc Lamp current and voltage measurements.
4.  Use a clamp-on type ammeter such as AMPROBE Model AC/DC 1000, or
equivalent, and measure the Arc Lamp current around the Ignitor cable. Place
the clamp-on current meter around either end of the white cable that goes
from the Ignitor to the Arc Lamp and measure the current going to the lamp
(Figure 3-3). If the current exceeds 70 amps, lower the current to 70 amps by
adjusting the...

Chapter 3---Service Adjustments
Model 230 Service Manual3-5
adjust the trimmer pot (Figure 3-4) until the result is 1600 ±30 watts. If
increasing, observe that the voltage from Step 4 may decrease slightly.
CAUTION! Make adjustments in small increments and do not adjust beyond
1630 watts or damage to the equipment may result.
5.  Wait approximately 10 minutes, then recheck the current and voltage and
make final adjustments, if necessary. Leave the front cover and lower-right
side panel off to perform the...

Chapter 3 Service Adjustments
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 Figure 3-5. Arc Lamp alignment screws.
9.  Once the hotspot is centered, use the same 3 alignment screws to obtain
proper rolloff from center to corners (rolloff is the gradual decrease in
brightness from the screen center to the screen corners). The goal now is to
decrease the brightness at the center and increase the brightness at the
corners. Rolloff should be no more than 4:1 from center to corners. Each
corner should be balanced evenly so...

Chapter 3---Service Adjustments
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 Figure  3-6.   Graphical representation of hotspot movement on screen.
 
Hot spot
off-center
Figure 3-7.   Arc Lamp “Hot Spot” (brightest area) is off-center vertically
and horizontally. Adjust to center the “hot spot”.
 
  

Chapter 3 Service Adjustments
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3.1.3   Condensing Lens Adjustment
NOTE: The Condensing Lens will not normally need adjustment and should not
be adjusted unless the hot spot is still significantly off-center and cannot be
centered using the Arc Lamp alignment screws. The first few steps of this
procedure are to prepare the Condensing Lens for adjustment and are performed
with power off. Then power is applied and the adjustments are performed.
1.  Turn off power to the projector...