BRUEL & KJAER Mediator 2238 - External Power Supply

Chapter 2 — Checking Procedure
Checking Procedure
2238 Mediator Integrating Sound Level Meter
Service Manual
BI5043–13
17
Table 2.7 Noise levels for different weightings
2.3.8 External Power Supply
Action:
● Remove the four batteries.
● Connect an external power supply to 7–15V and set the output voltage to 6VDC.
● Switch Type 2238 to ‘On’.
● Decrease voltage from the power supply to 4.5VDC.
Result:
● A ‘Battery Low’ warning must be flashing in the upper right hand corner of
the display.
Action:
● Decrease the voltage from the power supply further to 3.6VDC.
Result
● The 2238 switches ‘Off’ and the display goes blank.
● Remount the batteries.
The following tests can be performed with a Brüel&Kjær Type 4226 Multifunction
Acoustic Calibrator, or equivalent.
Frequency
Weighting
Value on
Display
Actual
Reading
Linear (LLSP) £ 26.0dB
A-Weighting (LASP) £ 19dB
C-Weighting (LCSP) £ 20dB