Dolby Laboratories CP65 manual 88 dBC

Page 58

5-38

B-Chain Alignment Procedures

e. Surround Equalization Alignment (Cat. No. 441)

Step

Action

Indication

No.

10

MONO SURROUND

STEREO SURROUND

Cat. No.

88 dBC

85 dBC

242

mono eq

mono

gain

non-syncL

R

OFF

0

80

0

60

50

0

3

7

4

L

signal

C

present R

Ls

gnd

L

test

C

points

R

Ls

Dolby

L

gain

C

R

Ls

11

RIGHT SURROUND AMP

ON

LEFT SURROUND AMP

OFF

12

Cat. No.

441

85 dBC

signal

present

tp

Subwoofer

on

cut

auto

freq

OFF

0

03

off

80

7

0

0

50

4

Q

6

n-sync

opt gain

surr

mag/dig

gain

gain

treble

Surround

cut

mid

freq

Q

Left

bass

tp

Dolby

treble

Surround

cut

mid

freq

Q

Right

bass

gain

gnd

signal

present

13

REPEAT

3

→ 10

5-39

B-Chain Alignment Procedures

e.Surround Equalization Alignment (Cat. No. 441) Notes

Adjust the Ls (Left surround) gain control on the Cat. No. 242 B-Chain card for a sound pressure level of 85 dBC (or 88 dBC if only one surround output is to be used).

If the surround speakers are wired for stereo operation or both surround outputs are in use, switch on ( or reconnect the input to) the right surround amplifier or amplifiers. Switch off (or disconnect the input to) the Left surround amplifier or amplifiers.

With the microphone still located at the center of the theatre, adjust the Right Surround gain control on the Cat. No. 441 surround and subwoofer card for a sound pressure level of 85 dBC.

Repeat Steps 3 through 10 using the Right Surround pots on the Cat. No. 441 card. NOTE: When you reach Step 10 remember that the right surround gain control is located on the Cat. No. 441 board.

Image 58

Contents Model CP65 Cinema Processor Dolby Laboratories Inc Headquarters Table of Contents Section Reference Block Diagrams Introduction Page Section Equipment Required Smpte Buzz Track Stereo Optical Surround Level Cat. No Jiffy Test Film Cat. No 2 Listen . . . Film Cat. NoSection Initial SET-UP and Installation Voltage Acceptable Setting Voltage Range Fuse Type Next, check the jumpers in the following locations Cat. No , Power Supply Module Cat. No , B-Chain CardCat. No , Control Logic Card J2 NON-SYNCCP65 Backplane Standard CP65 or CP65ACP65-300 High Low Subwoofer subwoofer Output output These Modules are Necessary for Bypass Operation Reduction Module Slot Card Function Cat. NoTwo-channel Noise Channel DecoderContains a semi-regulated power supply with Voltage Setting Fuse Type InternationalIEC Notices HUM Problems Room lighting dimmer controls SCR-TYPEPage Section AN Overview of the Alignment Procedure Aligning the B-ChainPage Page Section Chain Alignment Preliminary Procedures Action IndicationLamp Voltage Optical Preamplifier Adjustments Chain Alignment Procedures Optical Preamplifier Adjustments 222 CAT. no Test Film Oscilloscope Traces Repeat CAT no Repeat 1 →Magnetic Preamplifier Adjustments Magnetic Alignment 100mV Section Chain Alignment Setting Room Equalization BypassLoudspeakers and Crossovers Amplifiers GeneralChain Alignment Procedures OffRepeat ActionChain Alignment Procedures Setting Room Equalization Do not adjust Paul Setting Room Equalization b. Adjusting L,C,R Gain 14 → 21 R 14 →Setting Mono Gain 79 dBCChain Alignment Procedures Subwoofer Alignment Cat. No 90 dBC 85 dBCFrom Step NoSelect format 04 Dolby Stereo A-Type Same AS 441Surround Equalization Alignment Cat. No Surround Equalization Alignment Cat. No Notes Cat. No 441Desired 88 dBC Bypass Thumbwheel Switch Adjustment of Surround DelayMsec Setting Chain Alignment Procedures Adjustment of Bypass Gain Xx dBCFrom Xx dBC -3 dB Yy dBCAdjustment of Non-sync Gain Press the format 60 non sync switchAuto Freq Adjustment of Mono Gain and Equalization Notes Repeat page 5-20 StepChain Alignment Procedures Final Checks Press the format 04 Dolby Stereo A-type switchSection 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 15V +12B Cat. No +24V +15V+15M Appendix a Checking Phasing of Speakers Appendix B Effect of Changes in Slit Height on Slit Losses Operation Appendix C CP65M Mono InstructionsCat. No a Circuit Description Schematic Cat. No a Appendix D Backplane Connections List Terminal Block TB3Connector J18