130447-1 Rev. A

4.6.6 HEAD ROOM / INPUT CLIP LEVEL

Spec: < 1 % THD+N, with a +19.9 dBu input signal.

Initial Conditions: Input signal: 1 KHz, +19.9 dBu.

Procedure: Verify each main and AUX output meets spec.

4.6.7 INPUT POTENTIOMETER

Spec: ± 2 dB at the –12, and +20 dB settings.

Initial Conditions: Input signal: 1 kHz, 0 dBu in to all inputs.

Procedure: Verify each input potentiomenter by perfoming the following:

Set all potentiometers full counter clockwise. Verify each AUX output is –13 ±2 dBu.

Set potentiometer full clockwise.

Verify each AUX output is +20.5 ±2 dBu. Return potentiometer to the zero setting.

4.6.8 PHANTOM SUPPLY

Spec: 25.75 ±1VDC unloaded, between each signal pins (+, –) and chassis ground.

Initial Conditions: Remove all input signals and impedences. Set all inputs to phantom mode.

Procedure: For each input, Verify the DC voltage on the “+” and “–” pins referenced to chassis ground pin on all audio inputs.

4.6.9CONTROL PORT OUTPUT VOLTAGE PINS

Spec: Pins at rated voltage ±10%.

Procedure:.

Verify voltage between pins 9 and 10 of the control port is 5 ±0.25VDC.

Verify voltage between pins 29 and 28 of the control port is 10 ±0.5VDC.

4.6.10 CONTROL PORT LOGIC INPUTS

Spec: TTL level inputs are detected on the control port inputs.

Procedure:

Inject a TTL high on the odd numbered control port logic inputs (IN1, IN3, IN5, and IN7) and leave the even num- bered inputs open.

Use the following commands to read the control port inputs and verify the odd numbered inputs return $01 and the even inputs return $00:

Send: DA DT CT 80 50 0A CS; Get Control Port Digital Input 1

Return String: DA DT AK CT 80 50 0C IN1 CS

IQ-USM 810 Service Manual

Send: DA DT CT C0 50 0A CS; Get Control Port Digital Input 2

Return String: DA DT AK CT C0 50 0C IN2 CS

Send: DA DT CT 80 51 0A CS; Get Control Port Digital Input 3

Return String: DA DT AK CT 80 51 0C IN3 CS

Send: DA DT CT C0 51 0A CS; Get Control Port Digital Input 4

Return String: DA DT AK CT C0 51 0C IN4 CS

Send: DA DT CT 80 52 0A CS; Get Control Port Digital Input 5

Return String: DA DT AK CT 80 52 0C IN5 CS

Send: DA DT CT C0 52 0A CS; Get Control Port Digital Input 6

Return String: DA DT AK CT C0 52 0C IN6 CS

Send: DA DT CT 80 53 0A CS; Get Control Port Digital Input 7

Return String: DA DT AK CT 80 53 0C IN7 CS

Send: DA DT CT C0 53 0A CS; Get Control Port Digital Input 8

Return String: DA DT AK CT C0 53 0C IN8 CS

Inject a TTL high on the even numbered control port logic inputs (IN2, IN4, IN6, and IN8) and leave the odd numbered inputs open.

Use the above commands to read the control port in- puts and verify the even numbered inputs return $01 and the odd inputs return $00.

4.6.11 CONTROL PORT LOGIC OUTPUTS

Spec: Control Port Logical Outputs individually switch between On and Off.

Procedure:

Use the following commands to set the odd control port logical outputs and the even outputs off:

Send: DA DT CT 80 58 09 01 CS; Set Control Port Digi- tal Output 1 On.

Send: DA DT CT C0 58 09 00 CS; Set Control Port Digi- tal Output 2 Off.

Send: DA DT CT 80 59 09 01 CS; Set Control Port Digi- tal Output 3 On.

Send: DA DT CT C0 59 09 00 CS; Set Control Port Digi- tal Output 4 Off.

Send: DA DT CT 80 5A 09 01 CS; Set Control Port Digi- tal Output 5 On.

Send: DA DT CT C0 5A 09 00 CS; Set Control Port Digi- tal Output 6 Off.

Send: DA DT CT 80 5B 09 01 CS; Set Control Port Digi- tal Output 7 On.

Send: DA DT CT C0 5B 09 00 CS; Set Control Port Digi-

©2000 Crown International, Inc.

Maintenance 4-3

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Crown Audio IQ-USM 810 service manual Head Room / Input Clip Level