Troubleshooting - Crown MA-1202 Operation Manual

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.
Macro-Tech ODEP
and Signal/IOC Indicator Status
page 18
Indicator Status
OFF
ODEP
SIGNAL / IOC OFF
ODEP ON
SIGNAL / IOC OFF
ON
ODEP
SIGNAL / IOC Normal
ON
ODEP
SIGNAL / IOC Bright
Figure 6.1
OFF
ODEP
Bright
SIGNAL / IOC
OFF
ODEP
Normal
SIGNAL / IOC
Amplifier Condition
There is no power to the amplifier and all indicators are off, including the Enable light.
Possible reasons: (1) The amplifier's Enable switch is off. (2) The amplifier is not plugged into the power
receptacle. (3) The AC circuit breaker has been tripped. (4) The amplifier's low-voltage power supply
fuse has blown.
Normal operation for a channel with NO audio output. Possible reasons: (1) There is no input signal.
(2) The input signal level is very low. (3) The channel's level control is turned down.
Normal operation for a channel with audio output. The ODEP indicator will remain at full intensity
to show that there is reserve thermodynamic energy, and the Signal/IOC indicator will flash with normal
intensity to show that the channel has audio output.
The channel's output is exceeding 0.05% distortion. The input signal level is too high and IOC is
reporting either an input overload or output clipping.
Channel 2 only: The amplifier is in Parallel-Mono mode. The channel 2 Signal/IOC indicator always
turns on to full brightness whenever the amplifier's stereo/mono switch is set to Parallel-Mono mode.
The amplifier channel is in standby mode. Possible reasons: (1) A PIP module like an
IQ-PIP-Lite has turned off the channel's high-voltage power supply. (2) The amplifier has just been
turned on and is still in the four second turn-on delay. (3) The DC / low-frequency protection circuitry has
been activated. (4) The fault protection circuitry has been activated. (5) The transformer thermal
protection circuitry has been activated.
A channel's fuse has blown or breaker has tripped. Transformer overload can cause a channel's
internal fuse for its high-voltage supply to blow in a Macro-Tech 602 or 1202, and it can
cause the channel's circuit breaker to trip in a Macro-Tech 2402.
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 limiting is about to begin. 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.
MA Series Power Amplifiers
OR
OR
OR
Operation Manual