Speaker Unit Test; Ntc Module Test - Bang & Olufsen BeoLab 18 Service Manual

2.4 Troubleshooting

Speaker unit test

NTC module test

Measure the DC resistance of the speaker unit to determine if the fault is caused
by a defective speaker unit. It is recommended to measure on the terminals on the
speaker unit. The speaker units must be disconnected from the product.
Speaker unit Nominal value
Tweeter 6.3 ohm
Woofer 11.2 ohm
If the speaker unit is outside the limits, it is defective and must be replaced.
Under normal conditions it is not necessary to replace the gaskets on the speaker
unit, unless they have been damaged by accident.
Measure the resistance of the NTC module to determine if the fault is caused by a
defective speaker unit or a defective NTC module.
It is recommended to measure on the terminals on the NTC module.
The NTC module must be disconnected from the product.
The resistance of the NTC module at 22ºC (72ºF) is approximately 470k ohm.
If the NTC module is not measuring approximately 470k ohm, it is defective and
must be replaced.
Limits
5.7 - 6.9 ohm
10.0 - 12.5 ohm