Service manual

The signal goes from the input board to the control board to the amp heatsink
assembly which employs a Class AB/H amplifier.
Symptom: Unit faults or shuts down immediately upon power up
There are only two reasons that an HP/MP amplifier will shut itself off.
1) DC on one or all of the outputs
2) too high of temperature detected on the amp heatsink module.
The most likely module to cause DC voltage to be present on one or all of the
outputs is the amp HS assembly. The amp HS assembly is responsible for
delivering high currents to the drivers and is subject to high temperatures.
This module has built in protection for DC on the outputs or too high temperature.
Troubleshooting/solution:
Replace with a known good working module and see if the problem clears up in
the suspect unit and moves to the known good working unit.
SECTION II - Common Failure Modes
A. Circuit breakers trip on power up or during use –
2 Channel versions
1. Do not reset the circuit breakers.
If the circuit breakers are reset without first determining the cause of the
excessive current draw, further damage to the electronics may result.
2. If the amplifier is in the speaker cabinet, remove the eight (8) large diameter
Truss head Phillips screws that attach the amplifier to the cabinet. Remove the
amplifier from the cabinet slowly, taking care to unplug the green speaker
connector on the top side of the amplifier.
3. With the amplifier sitting on a firm surface, remove the four (4) flat head
Phillips screws from the amplifier chassis cover
and remove the cover over the
rear portion of the amplifier, above the fans.
4. Lay unit on its side and remove the six (6) screws from the bottom of the amp
chassis.
5. Return the unit to the upright position and disconnect the audio signal cable
from the control board by unlocking the gray ribbon cable connector.
6. Lift up the amp heatsink module in order to remove the white DC power
harness from the connector on the amp heatsink module.
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