Hughes JVC Projector 230 Service Manual
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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 Backplane PCB. Backplane PCB P8 P12 P14 P18 P9 P7 P72ALPS HVPSP43 P4P32 CDB P3P31 P10 P11 SCB P13RTG P16 P17 VPB P1P67 VAB P2P68 P6P36 HVDB P5P35 P19Proj LensP62 Fans P76LVPS VIC #1 VIC #2 VIC 3# Figure 2-17. Backplane Board Interface Block Diagram.
Chapter 2---System Description 2-60Model 230 Service Manual
Chapter 3---Service Adjustments Model 230 Service Manual3-1 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 .......................................................................... 3-10 3.3 ILA® Back Focus ..................................................................................... 3-10 3.4 CRT Mechanical Focus ............................................................................ 3-12 3.5 CRT Rotation ........................................................................................... 3-13 3.6 CRT Electronic Focus .............................................................................. 3-14 3.7 ILA® Overlap ........................................................................................... 3-15 3.8 Front/Rear or Inverted Projection Jumper Settings................................... 3-16 3.9 Vertical and Horizontal Size Settings........................................................ 3-18 3.10 Software Updating.................................................................................. 3-19 3.11 Gamma Tracking.................................................................................... 3-22 3.12 Graphic Enhancement Adjustment ......................................................... 3-23 3.13 Cleaning Lenses, ILA ® Assemblies and Mirrors...................................... 3-24 This chapter details adjustment procedures required to maintain the Model 230. Refer to Figures 3-1 and 3-2 to locate assemblies and components. A tool list, required to perform adjustments, is in Chapter 1. CAUTION! Before performing procedures in this chapter, review the chapter on Safety at the beginning of this manual. WARNING!!! When performing procedures in this chapter that require projector covers to be off, wear high voltage gloves (ANSI/ASTM 10,000 volt rated) when working near the CRTs, Arc Lamp, or power supplies. Wear safety goggles (rated X5) when working anywhere near the light path from the arc lamp or the projection lens.
Chapter 3 Service Adjustments3-2Model 230 Service Manual 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 needed, even when replacing an Arc Lamp. In rare instances, when the hot spot cannot be centered by the Arc Lamp alignment procedure, it may be necessary to perform the Condensing Lens adjustment. Do not perform the Condensing Lens adjustment unless absolutely necessary. 3.1.1 Arc Lamp Current Adjustment 1. Remove the front cover and the lower-right side panel. 2. Apply power to the projector and allow it to operate for a minimum of 15 minutes. 3. Use a DVM and measure the voltage across the Arc Lamp Ignitor ± terminals (see Figure 3-3). Caution: Always wear 10 kV rated rubber electrical gloves when performing the preceding operation. Also, Do Not place DVM leads across Igniter Terminals ± during projector power up because there is a 32 kV pulse that lights the Arc Lamp that is present across these leads during power up.
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 trimmer pot that is accessible through the small aperture in the Arc Lamp Power Supply cover (see Figure 3-4). CAUTION! The current should not exceed 75 amps or damage to the equipment could result. NOTE: If a clamp-on meter is not available, an alternate method of measuring Arc Lamp current may be used as follows: A. Using a DVM with the range set to a minimum of 100 millivolts, measure the Arc Lamp current by measuring the voltage across the two terminals, next to the trimmer pot from Step 5 above (Figure 3-4). This test point reads millivolts across a shunt that has been selected so that a 1 millivolt reading on the DVM is equal to 1 amp of Arc Lamp current. Figure 3-4. Zoom view of aperture on Arc Lamp Power Supply cover B. Multiply the voltage reading from Step 4 by the current measured in Step 5A (bear in mind that the millivolt reading from Step 5A should be interpreted as amps, i.e. 1 millivolt=1 amp. C. This result should be 1600 ±30 watts. If the result is not 1600 ±30watts, Arc Lamp current can be measured around either end of Ignitor cable. Measure Arc Lamp voltage across these Ignitor terminals.
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 Arc Lamp Alignment procedure. 3.1.2 Arc Lamp Alignment 1. Verify that the Shutters on Hide box is checked in the System-Preferences menu, then use the RGB key and the HIDE key to hide Red and Blue. This prevents light coming from the Red and Blue ILA ®s. 2. Open the fan door of the Arc Lamp Enclosure housing to gain access to the three Arc Lamp alignment screws. The Arc Lamp fan disconnects when this door is opened. CAUTION! This fan disconnection is acceptable for short periods of time only (preferably
Chapter 3 Service Adjustments 3-6Model 230 Service Manual 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 that no corner is excessively brighter or darker than any other corner. Be sure to adjust each of the 3 screws by the same amount, whether clockwise or counterclockwise, (adjusting any one screw more than the others will decenter the hotspot again). 10. After adjusting the 3 screws equally, recheck rolloff with the light meter again to determine if the screws need to be turned more in the same direction or in the opposite direction. Readjust, recheck, and readjust until a rolloff of 4:1 from screen center to screen corners is obtained. 11. When proper rolloff is obtained, return the ILA® bias adjustment to the level from Step 4, replace the fan door on the Arc Lamp Power Supply, retighten the fan door screws and recheck the Shutters on Hide box. If not performing a Condensing Lens Adjustment, replace the lower-right side panel and front cover. Adjustment screw 1 Adjustment screw 2 Adjustment screw 3
Chapter 3---Service Adjustments Model 230 Service Manual3-7 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 3-8Model 230 Service Manual 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 at the circuit breaker. Allow the projector to cool down for at least 5 minutes before proceeding. 2. Remove the front cover and lower-right side panel, if not already removed from above. 3. Remove the Dichroic Shield cover (first read the WARNING below) WARNING!!! Some components under the Dichroic Shield cover, especially the Condensing Lens and nearby components, are still hot! Before removing the Dichroic Shield cover wait at least 10 minutes for these components to cool down. 4. Loosen the two X-translation screws that hold down the Condensing Lens (see Figure 3-8). This allows the X (horizontal) alignment of the condensing lens. Figure 3-8. Condensing Lens, front view. 5. Loosen the hex Locking Screw (Figure 3-8) very slightly. This allows the Y (vertical) alignment of the condensing lens. 6. Turning the Y translation screw, located next to the locking screw (Figure 3-8) raises or lowers the lens. Rotating the screw clockwise raises the lens, rotating counterclockwise allow the lens to be pushed down manually. If the lens does not move freely, the four back screws may be too tight. To loosen Locking screw Y-Translation screwX-Translation screw