Dolby Laboratories CP65 manual Lamp Voltage

Page 29

4-4

A-Chain Alignment Procedures

a. Preliminary Procedures

	Step	Action	Indication
	No.	Action	Indication
	No.

4

70 TO 80%

OF RATED VOLTAGE

5

✓

4-5

A-Chain Alignment Procedures

a. Preliminary Procedures

Notes

Remove the existing exciter lamp and replace with a new lamp.

Adjust the exciter lamp DC voltage to 70% to 85% of the rated voltage and verify that there is no more than 3% ripple present with the lamp on, using an AC millivolt meter or oscilloscope. Do NOT attempt to extend the exciter lamp life by running at too low a voltage; the center of the slit may receive higher illumination than the edges, causing signal distortion.

LAMP VOLTAGE	DC ADJUSTMENT
6 V	4-5 volts
9 V	6.5-8 volts

If the projector uses a plastic light pipe or tube, verify that the light output is not appreciably affected by dirt, cracks or flaws, yellowing, or foreign matter. Replace if necessary.

Place a white card at a point behind the film plane. Then adjust the position of the exciter lamp until the image of the filament is centered both vertically and horizontally as shown.

You may find that obtaining an image of the filament is difficult in some projectors. Place a piece of tissue paper over the lens to assist in seeing the image of the filament. Some projectors do not use adjusting screws to change the position of the lamp; shims are sometimes used for positioning.

Image 29

Contents Model CP65 Cinema Processor Dolby Laboratories Inc Headquarters Table of Contents Section Reference Block Diagrams Introduction Page Section Equipment Required Jiffy Test Film Cat. No 2 Listen . . . Film Cat. No Smpte Buzz Track Stereo Optical Surround Level Cat. NoSection Initial SET-UP and Installation Voltage Acceptable Setting Voltage Range Fuse Type Next, check the jumpers in the following locations Cat. No , B-Chain Card Cat. No , Power Supply ModuleJ2 NON-SYNC Cat. No , Control Logic CardStandard CP65 or CP65A CP65 BackplaneCP65-300 High Low Subwoofer subwoofer Output output These Modules are Necessary for Bypass Operation Two-channel Noise Slot Card Function Cat. NoReduction Module Channel DecoderContains a semi-regulated power supply with International Voltage Setting Fuse TypeIEC Notices Room lighting dimmer controls SCR-TYPE HUM ProblemsPage Aligning the B-Chain Section AN Overview of the Alignment ProcedurePage Page Section Chain Alignment Action Indication Preliminary ProceduresLamp Voltage Optical Preamplifier Adjustments Chain Alignment Procedures Optical Preamplifier Adjustments 222 CAT. no Test Film Oscilloscope Traces Repeat Repeat 1 → CAT noMagnetic Preamplifier Adjustments Magnetic Alignment 100mV Section Chain Alignment Bypass Setting Room EqualizationLoudspeakers and Crossovers General AmplifiersOff Chain Alignment ProceduresAction RepeatChain Alignment Procedures Setting Room Equalization Do not adjust Paul 14 → 21 R 14 → Setting Room Equalization b. Adjusting L,C,R Gain79 dBC Setting Mono GainChain Alignment Procedures Subwoofer Alignment Cat. No 85 dBC 90 dBCStep No FromSelect format 04 Dolby Stereo A-Type 441 Same ASSurround Equalization Alignment Cat. No Cat. No 441 Surround Equalization Alignment Cat. No NotesDesired 88 dBC Bypass Msec Setting Adjustment of Surround DelayThumbwheel Switch Xx dBC Chain Alignment Procedures Adjustment of Bypass GainXx dBC -3 dB Yy dBC FromPress the format 60 non sync switch Adjustment of Non-sync GainAuto Freq Repeat page 5-20 Step Adjustment of Mono Gain and Equalization NotesPress the format 04 Dolby Stereo A-type switch Chain Alignment Procedures Final ChecksSection Reference Diagrams Cat. No Dual Noise Reduction Module Inputs Cat. No Optical Bass Extension and Surround Equalizer Card Cat. No B-Chain Facilities Card Cat. No Power Supply Card Cat. No Transformer Module Inputs Cat. No Control Logic Card +15M Cat. No +24V +15V15V +12B Appendix a Checking Phasing of Speakers Appendix B Effect of Changes in Slit Height on Slit Losses Cat. No a Circuit Description Appendix C CP65M Mono InstructionsOperation Schematic Cat. No a Terminal Block TB3 Appendix D Backplane Connections ListConnector J18