Crown Audio IQ-USM 810 Maintenance, General Information, Definitions, Required Test Equipment

130447-1 Rev. A

4 Maintenance

4.1 General Information

This chapter provides test procedures to be used to verify operation of this IQ component. Minimum speci- fications for proof of performance are given with each procedure. Procedures are in suggested format and the exact test need not be performed; however, the test conditions and results must be verified for proof of per- formance. These tests, though meant for verification and alignment, may also be very helpful in troubleshoot- ing. For best results, the tests should be performed in order.

4.2 Definitions

•IQ Ucode Protocol: The Protocol used by IQ2 prod- ucts for communication on the Crown IQ Bus.

•DA: IQ Ucode Device Address. A part of the Ucode string that identifies it as pertaining to a particular device. The DA for the IQ-USM 810 is set by the front panel controls. At first power up the IQ-USM 810 defaults to address $01.

•DT: IQ Ucode Device Type Identifier. A part of an Ucode string that identifies it as pertaining to a particular type of Ucode component. The DT for the IQ-USM 810 is $19.

•AK: IQ Message Acknowledgment. This byte is present in all Ucode device to host messages. It indicates if the last host to device message was correctly formatted.

IQ-USM 810 Service Manual

•CT: IQ Message data byte count. A part of the IQ string that indicates the number of bytes in its message portion. Note: This byte is automatically inserted when using IQ Util in enhanced mode.

•CS: Ucode Message Checksum. The last byte of a Ucode string containing the check sum of the entire message. Note: This byte is automatically inserted when using IQ Util in enhanced mode.

4.3 Required Test Equipment

Audio sine-wave generator (Output amplitude accuracy better than ±0.5 dB)

Oscilloscope

Audio THD+N analyzer True RMS AC voltmeter DC voltmeter

Audio multiplexer (balanced) or other means of switch- ing the audio generator to the eight mixer inputs.

Audio multiplexer (balanced) or other means of switch- ing the ten mixer outputs to the Audio analyzer and RMS voltmeter.

PC running applicable IQ Ucode compatible software Crown IQ Interface IQ-INT II or equivalent

Crown IQ standard 2000' test cables

Method of generating TTL Control Port inputs. Method of generating analog Control Port inputs. Method of measuring the Control Port outputs. Method of measuring the phantom power outputs.

WARNING

Circuitry is ESD sensitive. When servicing the IQ component, the technician must have approved ESD protection. Proper ground- ing straps and test equipment are required. Failure to use proper protection will result in component failure.

©2000 Crown International, Inc.

Maintenance 4-1