MA 2402 Power Amplifier
6 Troubleshooting
The table in Figure 6.1 shows the possible states for the ODEP and Signal/IOC indica- tors. It also describes the conditions that may be associated with the different indica- tor states. The Enable indicator will be off with the first indicator state, "There is no power to the amplifier." All other conditions in the table will occur with the Enable indi- cator turned on. It is important to note the possible states of the indicators in the rare event that you experience a problem. This can greatly aid in determining the source of problems. Please contact your local Crown representative or our Technical Support Group for further assistance.
Figure 6.1
and Signal/IOC Indicator Status
Indicator Status | Amplifier Condition | ||||
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ODEP |
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| OFF | There is no power to the amplifier and all indicators are off, including the Enable light. |
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| Possible reasons: (1) The amplifier’s Enable switch is off. (2) The amplifier is not plugged into the power | ||
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SIGNAL / IOC |
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| OFF | receptacle. (3) The AC circuit breaker has been tripped. (4) The amplifier’s | |
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| fuse has blown. | |||
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ODEP |
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| ON | Normal operation for a channel with NO audio output. Possible reasons: (1) There is no input signal. |
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| (2) The input signal level is very low. (3) The channel’s level control is turned down. | |||
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SIGNAL / IOC |
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| OFF |
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ODEP |
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| ON | Normal operation for a channel with audio output. The ODEP indicator will remain at full intensity |
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| to show that there is reserve thermodynamic energy, and the Signal/IOC indicator will flash with normal | |||
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SIGNAL / IOC |
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| Normal | intensity to show that the channel has audio output. | |
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ODEP |
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| ON | The channel’s output is exceeding 0.05% distortion. The input signal level is too high and IOC is |
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| reporting either an input overload or output clipping. | |||
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SIGNAL / IOC |
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| Bright | OR | |
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| Channel 2 only: The amplifier is in |
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| turns on to full brightness whenever the amplifier's stereo/mono switch is set to |
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ODEP |
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| OFF | The amplifier channel is in standby mode. Possible reasons: (1) A PIP module like an |
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SIGNAL / IOC |
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| Bright | turned on and is still in the four second | |
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| been activated. (4) The fault protection circuitry has been activated. (5) The transformer thermal | |||
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| protection circuitry has been activated. |
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| OR |
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| A channel’s fuse has blown or breaker has tripped. Transformer overload can cause a channel’s |
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| internal fuse to blow or can cause the channel’s circuit breaker to trip. |
OR
ODEP limiting has been activated. Possible reasons: (1) The amplifier’s air filters are blocked and need to be cleaned. (2) There is insufficient cooling because of inadequate air flow or air that is too hot.
(3)The load impedance for the channel is too low because the output is shorted or the amplifier is driving too many loudspeakers for the selected stereo/mono mode. (4) The amplifier channel is continuously being driven to very high output levels.
ODEP |
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| OFF | ODEP limiting is about to begin. Possible reasons: (1) The amplifier’s air filters are blocked and need |
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| to be cleaned. (2) There is insufficient cooling because of inadequate air flow or air that is too hot. | ||
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SIGNAL / IOC |
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| Normal | (3) The load impedance for the channel is too low because the output is shorted or the amplifier is | |
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| driving too many loudspeakers for the selected stereo/mono mode. (4) The amplifier channel is | |||
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| continuously being driven to very high output levels. |
page 18 | Operation Manual |
