Sennheiser HMEC 26 - Page 26

SENNHEISER ELECTRONIC GMBH & CO. KG
COMPONENT MAINTENANCE MANUAL
HMEC 26 SERIES
Page 1004
Feb 10/10
23-41-48
D. Operational test of the Talk Through function
NOTE:
THIS PROCEDURE IS ONLY APPLICABLE TO HMEC 26-T
E. Impedance measurement of the headset with Cable
ACTION RESULT
(1) To supply electrical power to the control
unit put two new fully charged batteries
into the control unit (only applicable to
-BV-KP, -BV-K, -B-K, -B-KP, -BV-CP and
-B-CP) or supply the required
NoiseGard™ operation voltage
(12 V DC to 35 V DC) via cable connector
(Ref. Fig. 1004).
(2) Set the NoiseGard
™ switch of the
control unit to ON.
(3) For Talk Through LED test
push the Talk Through button at the non
microphone side cap.
The two Talk Through LEDs on the left and right
capsule come on red.
(4) Push the Talk Through button at the non
microphone side cap again.
The two Talk Through LEDs on the left and right
capsule goes off.
(5) For Talk Through acoustic test
put on the headset (the two Talk
Through LEDs on the left and right
capsule are still off).
All low-frequency environmental noises are
decreased.
(6) Push the Talk Through button at the non
microphone side cap
(the two Talk Through LEDs on the left
and right capsule come on red).
You can hear some near field environmental
noises.
(7) Remove the headset.
ACTION RESULT
(1) Connect the multimeter (3, Table 1001)
to the related pins (Ref. Fig. 1004).
Note: Set the volume controls of
the relevant Cable to max. output level.
Set the mono/stereo switch to
stereo mode if applicable.
(2) Measure the impedance. Mono
(for cable -B-K, -B-KP, -BV-CP, -B-CP, -V-CP, -CP,
-NP and -KP): 480 ohms to 720 ohms
Stereo
(for cable -BV-KP, -BV-K, -V-RP, -V-KP and
-V-KX): 960 ohms to 1440 ohms
Oct 30/08