8.0 E4 System Troubleshooting

A number of fault conditions can be displayed in the Input Status section:

DC Sense Fault: A power supply fuse, output FET, amplifier mod- ule, or some combination of the above has blown. The unit should be replaced.

Amplifier Module Fault: When the Amplifier Module fault occurs by itself it can be caused by any of the following:

•Shorted speaker line – Check the loudspeaker line for shorts.

•System power exceeds 400W – Check that system power does not exceed 400W.

•Speaker transformer saturation – Check that proper speaker EQ is being used or use a high-pass filter for speaker EQ.

•Line voltage too high (surge) – Check Error Log for a rail volt- age that exceeds 150V, in 70V mode, or 190V, in 100V mode.

•Line voltage too low (brownout) – Check Error Log for a rail voltage which is lower than normal by at least 20%.

•70/100V mode switched with unit operating – Check that out- put voltage and AC input voltage selector are correct.

•Blown power supply fuse (as opposed to AC line fuse) – Replace the E4 unit.

AC Power Fault: Might be an AC line dropout or severe brownout, or simply AC power turned off without first placing the E4 in standby mode. You can check that the power has been removed from the E4, or that you experienced a power dropout.

Sleep Mode: The host microcontroller has told the amplifier and power supply to turn off. This only occurs in conjunction with another alarm (usually AC power fault), because it in itself is not an alarm condition. When an AC power dropout occurs, the amplifier immediately shuts the amplifier and speaker relay off, then the other processing is shut down. This all happens fast enough to prevent data loss or corruption, and to prevent loud pops in the speakers. When this occurs you should check the alarm history to determine what other faults occurred at this time.

High-Frequency Sense Fault: This protection mode is designed to prevent damage to the amplifier or speakers from excessive high-frequency audio or ultrasonic energy. The amplifier is not capable of sustained operation at full power in the 10kHZ to 20kHz (+) range.

Generally, this fault results in a one-time 3-second dropout. If, when the amplifier tries to restart after 3 seconds, the excess HF is still present, the amp (and speaker relay) will remain off for another 3 seconds and the loop repeats. Six of these in a row will cause the amp to shut down, and will trigger a Retry Fault.

When this fault occurs you can check your program material for excessive high-frequency content, or for a potential ground loop which has created an oscillation internal to the E4 unit. You can also reduce the output gain for this amplifier zone in an attempt to reduce the high-frequency energy going to the amplifier.

Retry Fault: The amplifier has tried to start up or recover from a fault condition at least six times. When this occurs, you will need to place the E4 unit in standby and then press the STANDBY but- ton again to clear the fault, at which time the E4 unit will again try to start up.

When this occurs you should check the alarm history section of the Amplifier Alarm to determine the exact fault type that trig- gered the Retry Fault.

Input and output alarm history

This part of the Error Log displays the sequence of fault condi- tions where “0” is the initial fault reported followed by “1-6”. These occur over a very short period of time.

8.3.5Solving faults reported in the Error Log

When errors are reported in the Error Log, you can try to solve the problem by performing one of the following actions:

•On the E4 rear panel, turn the POWER switch to OFF. Wait a few seconds and turn the POWER switch to ON. Then press STANDBY on the front panel.

•On the E4 rear panel, turn the POWER switch to OFF. Discon- nect all input/output signal cables. Wait a few seconds and turn the POWER switch to ON. Then press STANDBY on the front panel. Reconnect one cable at a time and check the Error Log.

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Bose E4 manual Solving faults reported in the Error Log, Input and output alarm history
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