BRUEL & KJAER 5998 User manual

Brüel BK
7/6-'89
& Kjær
BI5044–11
Technical
Documentation
Reciprocity Calibration Apparatus
Type 5998
Service Manual

June 1998
BI5044–11
Brüel & Kjær Reciprocity Calibration Apparatus Type 5998
Service Manual
Reciprocity Calibration Apparatus
Type 5998
Service Manual
Valid from serial number 2 021 566

0−2Brüel & KjærReciprocity Calibration Apparatus Type 5998
Service Manual
Safety Considerations
This apparatus has been designed and tested in accordance with IEC Publication
348, Safety Requirements for Electronic Measuring Apparatus, and has been supplied
in safe condition. This Guide contains information and warnings which must be fol-
lowed by the user to ensure safe operation and to retain the apparatus in safe
condition. Special note should be made of the following:
Safety Symbols
See the associated warning statements given in the User Guide.
Chassis Terminal
Safety Earth Terminal
Hazardous Voltage
Warnings
This is a CISPR II, Class A product. In a domestic environment this product may
cause radio interference in which case the user may be required to take adequate
measures
Switch off all power to equipment before connecting or disconnecting their digital
interface. Failure to do so could damage the equipment.
Whenever it is likely that the correct function or operating safety of the apparatus
has been impaired, it must be made inoperative and be secured against unintended
operation.
Any adjustment maintenance and repair of the open apparatus under voltage must
be avoided as far as possible and, if unavoidable, must be carried out only by trained
service personnel.
Copyright © 1998, Brüel&Kjær Sound and Vibration Measurement A/S
All rights reserved. No part of this publication may be reproduced or distributed in
any form or by any means without prior consent in writing from Brüel & Kjær Sound
and Vibration Measurement A/S, Nærum, Denmark.

Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 0−3
Contents
1. General Information.................................................................................................. 1–1
1.1 Edition Number........................................................................................................... 1–2
1.2 Safety ........................................................................................................................... 1–2
1.3 Service Policy............................................................................................................... 1–2
Electrical Repairs ................................................................................................... 1–2
Mechanical Spare Parts ......................................................................................... 1–2
1.4 Special Tools and Equipment ..................................................................................... 1–3
1.5 Introduction to Type 5998........................................................................................... 1–4
Front Panel............................................................................................................. 1–4
Back Panel........................................................................................................... 1–6
Lemo Pin Connections .......................................................................................... 1–7
2. Service Note...................................................................................................................... 2–1
2.1 On-line Editions of the Service Manual..................................................................... 2–2
2.2 Printed Editions of the Service Manual..................................................................... 2–2
3. Checking Procedure................................................................................................... 3–1
3.1 Introduction................................................................................................................. 3–2
Results not achieved............................................................................................... 3–2
Special Tools and Equipment ................................................................................ 3–2
3.2 Preparation.................................................................................................................. 3–2
3.3 Checking Procedure .................................................................................................... 3–3
Gain and Frequency Response, Channel A........................................................... 3–3
Gain and Frequency Response, Channel B........................................................... 3–4
Maximum Voltage and Distortion, Channel A ..................................................... 3–5
Maximum Voltage and Distortion, Channel B ..................................................... 3–6
Noise, Channel A.................................................................................................... 3–7
Noise, Channel B.................................................................................................... 3–8
High Pass Filters, Channel A ................................................................................ 3–9
High Pass Filters, Channel B .............................................................................. 3–10
Generator Input.................................................................................................... 3–11
Reference Signal................................................................................................... 3–12
Polarization Voltage............................................................................................. 3–13
Transmitter Unit ZE0796.................................................................................... 3–15

Reciprocity Calibration Apparatus Type 5998
Service Manual Brüel & Kjær
0−4
4. Calibration......................................................................................................................... 4–1
4.1 Polarization Voltage.................................................................................................... 4–2
5. Theory of Operation................................................................................................... 5–1
5.1 Introduction................................................................................................................. 5–2
5.2 Functional Description ............................................................................................... 5–2
Grounding Considerations..................................................................................... 5–3
Polarization Voltage............................................................................................... 5–4
Manual, Interface and PC Control........................................................................ 5–4
PC Control .............................................................................................................. 5–5
5.3 Block Diagram ........................................................................................................... 5–7
6. Mechanical Parts.......................................................................................................... 6–1
6.1 Mechanical Drawing................................................................................................... 6–2
7. Electrical Diagrams.................................................................................................... 7–1
7.1 Repair Policy................................................................................................................ 7–2
Schematic – ZD0817 Control Unit............................................................................ 7–3
Schematic – ZD0817 Control Unit............................................................................ 7–4
IEEE–488 Sub-section ........................................................................................... 7–4
Schematic – ZD0817 Control Unit............................................................................ 7–5
Gain Sub-section .................................................................................................... 7–5
Schematic – ZD0817 Control Unit............................................................................ 7–6
Output Sub-section................................................................................................. 7–6
Schematic – ZD0817 Control Unit............................................................................ 7–7
Filter Sub-section ................................................................................................... 7–7
PCB Layout – ZD0817 Control Unit......................................................................... 7–8
Board XM0454 ....................................................................................................... 7–8
Parts List – ZD0817 Control Unit............................................................................. 7–9
Schematic – ZE0792 Receiver Unit ........................................................................ 7–10
PCB Layout – ZE0792 Receiver Unit ..................................................................... 7–11
Board XM0456 ..................................................................................................... 7–11
Parts List – ZE0792 Receiver Unit......................................................................... 7–12
Parts List – ZE0792 Receiver Unit......................................................................... 7–12
Schematic – ZE0793 Transmitter Unit .................................................................. 7–13
PCB Layout – ZE0793 Transmitter Unit............................................................... 7–14
Board XM0456 ..................................................................................................... 7–14
Parts List – ZE0793 Transmitter Unit................................................................... 7–15
Schematic – ZG0395 Power Supply........................................................................ 7–16
PCB Layout – ZG0395 Power Supply..................................................................... 7–17
Board XM0457 ..................................................................................................... 7–17
Parts List – ZG0395 Power Supply......................................................................... 7–18
Schematic – ZH0453 Backplane ............................................................................. 7–19
PCB Layout – ZH0453 Backplane .......................................................................... 7–20
Board XM0458 – (component side)..................................................................... 7–20

Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 0−5
PCB Layout – ZH0453 Backplane .......................................................................... 7–21
Board XM0458 – (solder side)............................................................................. 7–21
Parts List – ZH0453 Backplane.............................................................................. 7–22
Schematic – ZH0454 Keyboard............................................................................... 7–23
PCB Layout – ZH0454 Keyboard............................................................................ 7–24
Board XM0459 – (component side) ..................................................................... 7–24
PCB Layout – ZH0454 Keyboard............................................................................ 7–25
Board XM0459 – (solder side)............................................................................. 7–25
Parts List – ZH0454 Keyboard................................................................................ 7–26
Schematic – ZH0455 Multiplexer............................................................................ 7–27
PCB Layout – ZH0455 Multiplexer ........................................................................ 7–28
Board XC2881...................................................................................................... 7–28
Parts List – ZH0455 Multiplexer............................................................................ 7–29
PCB Layout – ZH0456 Polarization Voltage.......................................................... 7–30
Board XC2882 – (component side)...................................................................... 7–30
PCB Layout – ZH0456 Polarization Voltage.......................................................... 7–30
Board XC2882 – (solder side).............................................................................. 7–30
Schematic – ZH0456 Polarization Voltage Selector............................................... 7–30
Parts List – ZH0456 Polarization Voltage Selector ............................................... 7–30

Reciprocity Calibration Apparatus Type 5998
Service Manual Brüel & Kjær
0−6

Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 1−1
Chapter 1
General Information

Chapter 1 — General Information
Edition Number
Reciprocity Calibration Apparatus Type 5998
Service Manual Brüel & Kjær
1−2
1.1 Edition Number
If any major changes are made to the instrument and/or Service Manual, a new
edition of the Service Manual will be released. Any new edition can be recognised
by the Literature Number (BI5044-xx) given at the bottom of odd numbered pages,
where xx is the edition number.
The serial number from which each edition is valid is printed in the frontispiece of
this Service Manual.
Information concerning minor changes will be released in the form of a Service
Note which is dealt with in Chapter 2.
1.2 Safety
Type 5998 and the equipment included with it has been designed and tested in
accordance with IEC Publication 348, Safety Requirements for Electronic Measur-
ing Apparatus, and has been supplied in safe condition.
Any work done on the instrument when open must be done by a qualified person
who is aware of the hazards involved, particularly ESD protection.
Note: The word WARNING denotes a hazard. It calls attention to a procedure,
practice, or like, which, if not correctly performed or adhered to, could result in
personal injury.
1.3 Service Policy
1.3.1 Electrical Repairs
Type 5998 and Microphone Fixture UA1412 and accessories are NOT part of the
FRP scheme. therefore, should Type 5998 fail the checking procedure, you must
repair the instrument locally or return it to Brüel&Kjær, Nærum.
To help you repair the instrument, a set of diagrams and schematics are given in
Chapter 7.
1.3.2 Mechanical Spare Parts
Mechanical spare parts can be ordered from Brüel&Kjær, see Chapter 6 for details
of the parts available and their part numbers.

Chapter 1 — General Information
Special Tools and Equipment
Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 1−3
1.4 Special Tools and Equipment
To perform the checking procedure, troubleshooting and adjustment of Type 5998,
the following special tools and equipment must be available:
Type 1049/51 Sine Generator
Type 2610/2636 Measuring Amplifier
Digital Voltmeter
Oscilloscope
28V DC Power Supply
AO0479 BNC to Lemo, 1.2m
JJ2617 Microphone to 10–32UNF converter
JP0169 10–32UNF shorting plug

Chapter 1 — General Information
Introduction to Type 5998
Reciprocity Calibration Apparatus Type 5998
Service Manual Brüel & Kjær
1−4
1.5 Introduction to Type 5998
The electronics of Type 5998 are mains powered and built into a robust casing
which has two microphone channels, one of which is used for the transmitter and
the other for the receiver. The instrument also includes a high-precision 200V po-
larization voltage supply. The polarization voltage can be checked using the exter-
nal digital voltmeter, and adjusted to the correct level using a front-panel
adjustment. As an alternative, an external polarization voltage can be applied. See
the block diagram in section 5.3 for more details.
Each channel has built-in relays to allow external control of the apparatus via its
IEEE–488 interface bus and selection of the required measurement configurations.
This allows PC control of an automatic sequence to measure the transmitter/receiv-
er electrical transfer impedance at all selected frequencies
1.5.1 Front Panel
This section details the functions of the controls, connectors and indicators on the
front panel.
Channel A: Receiver: 7-pin LEMO socket for connection of the signal from the re-
ceiver microphone. Pin connections are shown in Fig.1.3.
Polarization Voltage: 3-position sliding switch for selection of 0V,
+200V microphone polarization voltage or an external polarization volt-
age.
Overload: Red LED which lights when there is an overload (>10Vpeak)
on channel A.
Channel B: Transmitter: 7-pin LEMO socket for connection of the signal to/from
the transmitter microphone. Pin connections are shown in Fig.1.3.
Polarization Voltage: 3-position sliding switch for selection of 0V,
+200V microphone polarization voltage or an external polarization volt-
age.
Overload: Red LED which lights when there is an overload (>10Vpeak)
on channel B.
Ref. Adj.: ±10dB potentiometer for adjusting the level of the reference
signal. The level can be measured using the Ref. Signal Output socket
on the back panel of the apparatus.
Gain: Two pushkeys for increasing or decreasing the gain applied to a signal
(both channels). Range: 0 – 50dB in 10dB steps. The setting is indicat-
ed by one of the green LEDs above the pushkeys.

Chapter 1 — General Information
Introduction to Type 5998
Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 1−5
Output: Two pushkeys for selecting the signal applied to the Output socket on
the back panel of the apparatus. You can select the channel A or chan-
nel B signal, the reference signal or the generator signal including the
internal gain. The setting is indicated by one of the green LEDs above
the pushkeys.
HP Filter: Two pushkeys for selecting the 1, 20 or 100Hz high-pass filter. The
setting is indicated by one of the green LEDs above the pushkeys.
Fig.1.1 The front panel of Type 5998
Ref.: Pushkey for toggling the reference signal on pin 1 of the channel A and
channel B sockets on or off. The reference signal is on when the green
LED to the right of the pushkey is lit.
Local: Pushkey for setting Type 5998 to local mode, for manual control. There
is no IEEE command for Local LockOut.
Remote: Green LED which lights when Type 5998 is being operated remotely, for
example when using the measurement program.
Polarization Voltage: Adj.: ±1V potentiometer for adjusting the internal 200V polarization
voltage.
200V and :Banana sockets for connection of voltmeter when measur-
ing and adjusting the internal 200V polarization voltage.
Overload Overload 010 20 30 40 50
970557
e
ABRef.Gen.
Gain
Output
1 20100 Hz
Channel B
Channel A
Receiver Transmitter
HP Filter
Ref. Local
Remote
Polarizaton Voltage
0V 200V Ext.
Polarizaton Voltage
0V 200V Ext.
Reciprocity Calibation Apparatus Type 5998
Ref. Adj.
Polarization Voltage
Adj. 200 V
BK
7/6-'89
Brüel & Kjær

Chapter 1 — General Information
Introduction to Type 5998
Reciprocity Calibration Apparatus Type 5998
Service Manual Brüel & Kjær
1−6
1.5.2 Back Panel
Fig.1.2 Back panel of Type 5998
Mains Connector: On/off switch, mains connector and fuses.
Signal GND: Two-position sliding switch for selection of Chassis or Floating
signal ground.
Interface Bus: Standard IEEE–488 interface bus connection for remote control
of the apparatus.
Ref. Signal Output: BNC socket for output of the reference signal.
Channel B Output: BNC socket for output of the channel B signal.
Generator Input: BNC socket for input of the signal from an external generator
(max. 6Vpeak). The input applies a gain of 6dB to the generator
signal.
Output: BNC socket for output of the signal selected using the Output
pushkeys on the front panel of the apparatus: channel A, channel
B, reference or generator (with 6dB gain).
Ext. Polarization
Voltage Input: BNC socket for input of an external polarization voltage.
970558e
I
0
Fuses: 90-140V : T 160mA
180-254V : T 80mA
50-60Hz 25VA
Signal GND
Interface Bus
IEEE-488
Ref. Signal
Output
Channel B
Output
Output
Generator
Input
Ext. Polarization
Voltage Input
Chassis
Floating

Chapter 1 — General Information
Introduction to Type 5998
Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 1−7
1.5.3 Lemo Pin Connections
Pin Channel A Receiver Channel B Transmitter
1 Reference on: Insert Voltage (Reference Signal)
Reference off: Signal Ground
2 Signal Ground
3 Polarization Voltage
4 Signal Output
5 Signal Ground Reference on: Signal Output
(i.e., connected to pin 4)
Reference off: Generator Signal
6 Power Supply, Positive
7 Power Supply, Negative
Fig.1.3 Channel A Receiver and Channel B Transmitter connections
960472e
2
7 pin LEMO
7
3
456
1

Chapter 1 — General Information
Introduction to Type 5998
Reciprocity Calibration Apparatus Type 5998
Service Manual Brüel & Kjær
1−8

Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 2−1
Chapter 2
Service Note

Chapter 2 — Service Note
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Reciprocity Calibration Apparatus Type 5998
Service Manual Brüel & Kjær
2−2
2.1 On-line Editions of the Service Manual
From time to time some minor changes may be made to improve the performance
and serviceability of Type 5998. All information concerning these changes, or any
other changes to the service manual, are included in the latest version of the on-
line source document.
This Service Note section contains a history of the changes.
2.2 Printed Editions of the Service Manual
From time to time some minor changes may be made to improve the performance
and serviceability of Type 5998. All information concerning these changes, or any
other changes to the Service manual, will be released in the form of a Service Note.
Note: The Service Note is renewed as a whole, meaning:
Discard the previous Service Note every time you receive a new one
The new edition of the Service Note must be placed in the binder in this section.
The organisation of the Service Note is as in the Service Manual, i.e. the Service
Note is divided into sections with names corresponding to the section name in the
Service Manual.

Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 3−1
Chapter 3
Checking Procedure

Chapter 3 — Checking Procedure
Introduction
Reciprocity Calibration Apparatus Type 5998
Service Manual Brüel & Kjær
3−2
3.1 Introduction
WARNING: The polarization voltage terminals on the front panel produce up to
200VDC.
The following Checking Procedure for Type 5998 is a subset of the final factory test.
The Checking Procedure verifies that the functionality of Type 5998 is correct.
The Checking Procedure is intended to be performed on a fully assembled instru-
ment.
3.1.1 Results not achieved
If the expected result is not achieved when a certain check is done, you must decide
if the unit requires repair. Refer to section 1.3 for details of the service policy.
3.1.2 Special Tools and Equipment
See section 1.4.
3.2 Preparation
1. Apply power to Type 5998 and allow it to stabilise for 30 minutes.
2. Check of the Instrumentation
Before starting the Checking Procedure, it is advisable to check that the output
from the Sine Generator Type 1049/51 matches the read-out on the voltmeter,
the measuring amplifier and the oscilloscope.
a. Set 1kHz at 1V on Sine Generator Type 1049/51
b. Measure this signal, via a direct BNC–BNC connection, to the;
Voltmeter
Measuring Amplifier Type 2610/2636
Oscilloscope
And ensure that the signal levels agree.
3. Set the Signal Ground switch on the rear of Type 5998 to Chassis.

Chapter 3 — Checking Procedure
Checking Procedure
Reciprocity Calibration Apparatus Type 5998
Service Manual
BI5044–11 3−3
3.3 Checking Procedure
3.3.1 Gain and Frequency Response, Channel A
1. Set the front panel controls on Type 5998 as follows:
2. Apply 1V at 1kHz to the Channel A Receiver input using cable AO0479.
3. Use the Measuring Amplifier to check there is 1V on the Output BNC socket.
4. Change the frequency to 200kHz. The output should still be 1V.
5. Reduce the frequency towards 1Hz and check that the frequency response is flat
until 50Hz. By 20Hz the level should fall by –3dB.
6. Reduce the generator signal by 10dB and increase the front panel Gain by
10dB.
7. Repeat the measurements from step 3. for all gain settings (i.e. 10dB, 20dB,
30dB, 40dB, 50dB).
Control Setting
Gain 0
Output A
HP Filter 20
Ref. Off
Polarization Voltage 0