Repair Tips - Bang & Olufsen BeoLab 7-1 Service Manual

Repair tips

Hum in loudspeaker when no music is played.
Power Link
Mk 3
Stand by LED
No power on outlet
Speaker unit check
The Power Link cable must be of type MK 3 or higher.
The ground connection in Power Link cable lower than MK 3 may be insufficient
for optimum sound performance.
The Standby LED indicates the status of the BeoLab 7 – 1.
Access to Standby LED.
Stand by LED STATUS
Red BeoLab 7 – 1 is in standby.
Green BeoLab 7 – 1 is operating.
Orange BeoLab 7 – 1 is shut down due to thermal overload.
No light Fuse may be defect, check fuse F501 on PCB5
Pay special attention to the gaskets for baffle
If the LED Status is Orange, turn off and disconnect the mains to the BeoLab 7 – 1.
Wait for minimum 5 minutes for the loudspeaker to cool down.
Connect mains and turn on the BeoLab 7 – 1.
If the LED status still is orange the fault may be due to:
1. Woofer protection - Perform speaker unit check.
2. Tweeter protection - Perform speaker unit check.
3. Midrange protection - Perform speaker unit check.
4. NTC- board or connection on one of the woofers.
Access the NTC-board by dismantling the woofer.
5. Power supply failure.
Check Fuse on PCB1
Pay special attention to the gaskets for baffle
Measure the impedance of the speaker unit to determine if the fault is caused by a
speaker unit.
It is recommended to measure on the terminals on the speaker unit.
The speaker unit must be dismantled from the BeoLab 7 – 1.
Pay special attention to the gasket on the speaker unit.
Speaker unit Nominal value
Woofer 6.1 ohm
Midrange 6.1 ohm
Tweeter 6.1 ohm
If the speaker unit is outside the limits, it is defect and must be replaced.
Under normal conditions it is not necessary to replace the gaskets on the speaker
unit.
Repair tips
Limits
5.6 - 6.7 ohm
5.6 - 6.7 ohm
5.6 - 6.7 ohm
3