BRUEL & KJAER 2203 Service

BROEL & KJA:R
Ncerum - Denmark
Checking and Adjusting
2203.1
A direct acoustical calibration using the Pistonphone Type 4220 or the
Sound Level Calibrator Type 4230 always ensures correct sound level
measurements, while an electrical calibration using the built -in refer-
ence
voltage relies on the tolerance of this ref . voltage as well as the
polarization voltage for the microphone .
Sensitivity Check
Att . black: " Ref."
Att . transp .: " Ref ."
Meter Switch : " Lin.- Fast"
Att. black to " 1 20 dB" with 4220
or " 90dB " with 4230
Sensitivity Adjustment
Att . black: " 120 dB"
Att. transp .: " 120 dB"
Meter Switch : " Lin. -Fast "
Att . black to " Ref."
(rear)
0
co mm on gr ound conn ect ion
Ref.
._ ____ _,
Sensitivity Trouble Shooting
Input signal: 3.45 V RMS
at 1 kHz through adaptor
Type
JJ 2614
I
Input
Amplifier
I
Input
Att .
120d8
I
I
Adj
(at OdBRef.l
In
The following procedure describes how the tolerance of the electrical cali-
bration is checked in an easy way .
2203 fitted with a One-inch Microphone f.inst. Type 4145.
Turn " Adj ." to indicate the K- factor of the Microphone , where K is equal to Ko + 1,2 dB (ca -
pacitive
attenuation in the 2203 input stage).
Place the Pistonphone or Sound Level Calibrator over the Microphone , ensure that it is firmly
seated, and switch on the calibrator.
The 2203 Meter should now indicate the correct sound pressure level according to the cali-
bration chart of the calibrator (corrected if necessary for atmospheric pressure).
The
deflection should be within ± 0,2 dB of the expected result .
Small
deviations may be corrected by carrying out the following Sensitivity Adjustment .
However, in case of larger deviations , the Trouble Shooting with associated adjustment
should be consulted .
Apply 1kHz at exactly 2, 21 V RMS to the input of 2203 through adaptor JJ 2614 .
Turn "Adj ." to indicate 6 dB on the meter of 2203 .
Adjust " Ref ." to indicate OdB on the lower red scale.
The " Pol. Voltage" should be adjusted to 200 V which is measured on the slider of the poten-
tiometer , either by means of a Differential Voltmeter , or by means of an ordinary DC Voltme-
ter and a 200 V Reference Supply (f.inst . the Pol. Voltage of a Microphone Amplifier 2606,
2607 etc.)
After adjustment the acoustical Sensitivity Check should be within ± 0,2 dB.
Ext . Filter
Out
316mV.
Output
3J6V
I
I
I
I
I
I
I
Meter
Switch
Lin . Fast
Output
Ampl ifi er
I
I
Output
Att .
120 dB
Full Scale
Indication
By means of the simplified diagram it is possible to localize a sensitivity
problem to be in the Input Amplifier, the Output Amplifier or the Meter
Circuit.
The current consumption from the batteries should be approx. 125 mA
and the converter frequency approx. 1000Hz .
In
case of divergence between Meter reading and Output Voltage P 401
should be adjusted for full scale deflection with exactly 3, 16 V RMS on
Output. If this is not possible check the meter diodes.
If one of the amplifiers is found defective the corresponding sensitivity di-
agram
should be consulted.
If none of the amplifiers seem to be functioning the Power Supply should
be examined .
P
603 should be adjusted for -9 V ± 0, 1 V on the negative end of C
601.
However , the adjustment of P 603 will influence all the other voltages
as
well , for which reason the Sensitivity Adjustment procedure must be
consulted again .
With Meter Switch in position " Batt .", the condition of the batteries is
shown on the meter.
P 601 should be adjusted in such a way that the indication deflects the
lower mark on the Battery scale with a battery voltage of 3,0V .
9. 73
Valid from serial no. 467 1 52
1-1

BRUEL & KJAER 2203 Specifications

General

Brand	BRUEL & KJAER
Model	2203
Category	Measuring Instruments
Language	English