Crown Audio IQ-USM 810 - Manual (Page 21)

©2000 Crown International, Inc.
Maintenance 4-1
130447-1 Rev. A IQ-USM 810 Service Manual
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.
• 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.