Chapter 2 — Checking Procedure
Checking Procedure
2238 Mediator Integrating Sound Level Meter
Service Manual
Brüel&Kjær
12
2.3.1 Visual Inspection of the Microphone
Action:
● Remove the protection grid from the microphone, inspect and remount
Results:
● No holes, corrosion, scratches or other visual damage to the diaphragm
Fig.2.1 Typical setup for Checking Procedures
2.3.2 Outputs– Analog Output
Action:
● Remove microphone and use adaptors JJ2614 and JP0144 to connect the
generator to the 2238. Use a LEMO to BNC cable to connect the 2238’s DC Output
(Aux1 plug) to a multimeter.
● Press to switch the 2238’s power on. Press , then to select General.
● Press to set Range to 50.0 - 130.0 dB. Press to OK, then and to se-
lect Weightings. Use to select BB/F on the Bandwidth line. Use to go to
the Freq. Wgt. line, and press until the display reads L. Press to OK
and to Close.
● If the first line of the “active” display doesn’t read LLFP, then press to go to the
first parameter and use until it does (there are 10 possible settings). Press
or to return to the “active” display.
● Apply an input signal of approx. 126dBµV at 1kHz, so that the 2238 display reads
130.0 dB. Check the DC output voltage according to Table 2.1.
● Switch the cable to the 2238’s AC Output (Aux2) and repeat.
980564e
Sine/Noise Generator
1049
Multimeter
2238
JP 0144
JJ 2614
Serial Output
AC Output
(AUX 2)
0
Brüel & Kjær Type 2236
DC Output
(AUX 1)
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