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9.4
Short circuit protection
All Martin Audio MA Series amplifiers are completely short circuit protected. The protection circuit permits very high
peak currents, but still holds the output devices within the safe operating area. If a short circuit is maintained, the
channel affected will eventually go into a thermal protect cycle until the short circuit has been removed.
9.5
AC mains voltage protection
If the AC mains voltage is outside the operational window (over or under voltage), the power supply will
automatically shut down. When the mains voltage is above the minimum start voltage and below its maximum
operating voltage the amplifier will restart.
The two green 'ON' LED's indicate when the power supply is operating correctly.
It takes a couple of seconds to self-check (this is known as the "soft start" or "slow start" sequence), the gain will
slowly and gradually be increased back to the previously set level, and the fans will blow at high speed before
going into "idle".
9.6
DC protection
There are two types of DC protection:
10 MAINTENANCE
Under normal use the amplifier should provide years of trouble-free service. The only maintenance required by the
user is to clean the front grill periodically.
In some extreme cases it may be necessary for authorized service personnel to clean the inside of the amplifier.
These conditions usually occur after prolonged use, e.g. in environments using "cracked- oil" smoke machines.
If you are using your amplifier for heavy duty use i.e. concert touring or industrial music it is recommended that you
have your amplifier serviced every 3 years, purely as a preventative measure.
10.1 Troubleshooting
These are typical things to check if you think your amplifier is faulty:
Fault: No output.
If the signal present LED (-40dB) is illuminating a signal is entering the amplifier; and the likely cause is an
unsecured Speakon connector, or loose termination
Check also that the VHF protection is not activated. If it is, remove the cause of the high frequency oscillations from
the relevant input.
Fault: The amplifier goes into thermal protection when driven at low level.
Check that there is no short circuit present at the amplifier's output, e.g. any component in the loudspeaker (this
can occur when the loudspeaker voice coil gets hot).
Fault: The amplifier goes into protection with power indicators off.
Check that the AC mains voltage is within the amplifier's operating range, 130-270V and (65-135V @ 115V).
Over/under-voltage protection may have occurred. If the amplifier is connected by mistake to a 3-phase supply
(415V), an internal non-resetable fuse or resistor may have blown. The amplifier must then be returned to your
supplier for service/ repair.
Fault: The amplifier does not respond even after checking above items.
In the unlikely event of on a non-user rectifiable fault, return the amplifier to your supplier or an approved service
centre.
Martin Audio cannot be held responsible for damage or injury as a result of the top cover being removed.
All material © 2007. Martin Audio Ltd. Subject to change without notice.
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Fuses on the supply branches of each channel.
DC crowbar protection that shorts the output if more than 10 volts DC is being detected on the outputs.
Both these circuits come into effect once a DC level has been detected on either channel.
Martin Audio – MA1.3s Amplifier
14
GUIDES
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