Functional Test Activegard™ (Hmd/Hme 26); Functional Test Noisegard™ (Hmdc 26) - Sennheiser HME 26-600 Service Manual

6.3 Functional test ActiveGard
STEP
Set the "ActiveGard" switch to "OFF", if needed.
Supply the AF signal (1 kHz/2 Veff) via AF generator
(1 kHz/2 Veff) to the related pins of the cable´s connector:
Audio Hi/Audio Lo left and Audio Hi/Audio Lo right.
Adjust the AF generator: The 2 V
headset´s input connectors.
Measure the electrical output signal at the microphone side:
Transducer +/- (signal at the left channel) and
Loudspeaker +/- (signal at the right channel)
1 kHz test signal Measure the level at the transducer +/-
at the headphone ActiveGard switch = OFF
input
2 V 1.85 V
eff
6.4 Functional test NoiseGard
STEP
Insert 2 completely charged alkaline batteries
(type LR 6 = AA, 1.5 V) or 2 rechargeable batteries.
Put on the headset and switch on NoiseGard via operating control. Ambient noises/low frequencies are hearable downsized/
(HMD/HME 26)
™
amplitude is available at the
eff
±100 mV
eff
(HMDC 26)
™
RESULT
See table below
See "PCB of the acoustic units of the HMDC 26", page 22.
See "PCB of the acoustic units of the HMD/HME 26", page 23.
Measure the level at the transducer +/-
ActiveGard switch = ON
±130 mV
420 mV
eff
RESULT
decreased.
HMD/HMDC/HME 26 Broadcast
08/2011 20/23