Electro-Voice CPS 3, Руководство по обслуживанию

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5.7. DC-VOLTAGE-PROTECTION TEST
•
HI/LO-Cut off, Limiter set to SLOW
testing has to be performed for both channels of the power amplifier individually:
-
drive the power amplifier with a test signal (f = 7 Hz) and without load resistor connected.
- at an input voltage of approx. 4 Vpeak the protection circuit reacts and tries continuously to re-start!
The protect-LED blinks with the same frequency.
-
Repeat the test with f = 14 Hz; the power amplifier should not switch off.
5.8. HF-PROTECTION TEST
Caution: it is mandatory to drive the power amplifier without load resistors connected. Set the fan service
switch to ON and the HI/LO-Cut to OFF. Switch off the limiter via S102 or by disconnecting the bridge
between CNASERV 1 and CNASERV 3. Drive the power amplifier with a with 7 Vrms and a sine burst of
f =
60 kHz (100 ms ON, 900 ms OFF), applied to each channel at a time. The protection circuit has to react. The
power amplifier tries to re-start continuously while the PROTECT LED blinks with the same frequency.
Repeat the test with
f = 30 kHz and the limiter set to ON; the power amplifier should not switch off.
6. Level CHANNEL A&B:
• set the level control to its fully clockwise position.
• set the INPUT ROUTING switch to: DUAL / STEREO.
• HI-LOW-CUT switch is ON (as factory pre-set!).
• BRIDGED MODE: NORMAL
• LIMITER: SLOW (as factory pre-set!)
• THD < 0.1 %
6.1. NOMINAL LEVEL
Input U(E) Measuring point U(A) Load resistor Jumper on
86208/86212
CH. A/B 0 dBu SPEAKER A/B 56.6 V 4 Ohm select J11,J21
CH. A/B + 6 dBu SPEAKER A/B 56.6 V 4 Ohm select J12,J22
CH. A/B + 13 dBu SPEAKER A/B 56.6 V 4 Ohm select J13,J23
CH. A/B +1 dBu SPEAKER A/B 63.2 V 8 Ohm select J11,J21
CH. A/B -2 dBu SPEAKER A/B 44.7 V 2 Ohm select J11,J21
6.2. MAXIMUM INPUT LEVEL: U(E) = +21 dBu (8.7 Vrms)
7. INPUT-ROUTING switch
DUAL / STEREO (as factory pre-set!)
- channel A and B have to be driven separately.
PARALLEL / MONO
- channel A and B are paralleled at the input. Both channels can be driven using a common signal
source.
8. Level BRIDGED MODE
• set the level control all the way to its fully clockwise position.
• HI-LOW-CUT switch is ON (as factory pre-set!).
• BRIDGED MODE: BRIDGED
• LIMITER: SLOW (as factory pre-set!)
• THD < 0.1 %
BRIDGED: Double the output voltage is presented at the BRIDGED OUT connector. It is mandatory to use the
CHANNEL A input connector. The CHANNEL B input connector is without function.
Input U(E) Measuring point U(A) Load resistor Remarks
CH. A 0 dBu BRIDGED OUT 89.4 V 4 ohms select J11,J21
CH. A 0 dBu BRIDGED OUT 113.2 V 8 ohms select J11,J21
9. GROUND LIFT switch
Test the functioning of the switch using an ohm-meter:
The circuit ground (at the input or the output connector) is measured versus the common ground of the
enclosure (contact at the ground terminal, located on the rear panel - or common ground of the mains cord).