BRUEL & KJAER 2825 User manual

Brüel&Kjær
BI5033–12e
Technical
Documentation
WORLD HEADQUARTERS: DK-2850 Nærum • Denmark •
Telephone: [phone] •Telex: 37316 bruka dk • Fax: [phone] •
e-mail: [e-mail]
Acquistion Front-end
Type 2825
Service Manual

0−2Brüel & KjærAcquisition Front-end Type 2825
Service Manual
Proprietary: Authorized Brüel & Kjær Personnel Only

April 1997
BI5033–12e
Brüel & Kjær Acquisition Front-end Type 2825
Service Manual
Acquisition Front-end
Type 2825
Service Manual
Valid from serial number 1 904 567

0−2Brüel & KjærAcquisition Front-end Type 2825
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 © 1997, 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.

Acquisition Front-end Type 2825
Service Manual
BI5033–12e 0−3
Contents
1. General Information.................................................................................................. 1–1
1.1 Introduction................................................................................................................. 1–2
1.2 Edition Number........................................................................................................... 1–2
1.3 Safety ........................................................................................................................... 1–3
1.4 Service Policy and FRP Number ................................................................................ 1–3
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
3.2 Checking Procedure .................................................................................................... 3–2
3.3 Test of ventilator......................................................................................................... 3–2
4. Adjustment Procedure............................................................................................. 4–1
4.1 Introduction................................................................................................................. 4–2
4.2 Procedure..................................................................................................................... 4–2
5. Troubleshooting............................................................................................................. 5–1
5.1 Introduction................................................................................................................. 5–2
5.2 Procedure..................................................................................................................... 5–2
5.3 Cooling fan................................................................................................................... 5–2
6. Routine Maintenance................................................................................................ 6–1
6.1 Routine Maintenance.................................................................................................. 6–2
Cleaning of Air-filter .............................................................................................. 6–2

Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
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7. Mechanical Parts.......................................................................................................... 7–1
7.1 Dismantling Procedure............................................................................................... 7–2
Removing the Power Supply.................................................................................. 7–2
Removing the Backplane ....................................................................................... 7–3
7.2 Mains Switch and Fuseholder.................................................................................... 7–3
7.3 Fan Assembly UH1022............................................................................................... 7–4
7.4 Mechanical Parts List................................................................................................. 7–4

Acquisition Front-end Type 2825
Service Manual
BI5033–12e 1−1
Chapter 1
General Information

Chapter 1 — General Information
Introduction
Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
1−2
1.1 Introduction
Acquisition Front-end Type 2825 is a frame for housing modules for use in Type
3550, Type 3551 and Type 3560 (PULSE) systems.
1.2 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 (BI5024-xx) given at the bottom of odd numbered pages.
The serial number from which each edition is valid is printed in the Frontispiece of
this Service Manual.
Fig.1.1 Type 2825

Chapter 1 — General Information
Safety
Acquisition Front-end Type 2825
Service Manual
BI5033–12e 1−3
Information concerning minor changes will be released in the form of a Service
Note which is dealt with in section 2.1.
1.3 Safety
Type 2825 has been designed and tested in accordance with IEC Publication 348,
Safety Requirements for Electronic Measuring 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.
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.
1.4 Service Policy and FRP Number
Type 2825 itself is not a Field Replaceable Part (FRP). If any of the mechanical
parts in Type 2825 fail, they need to be replaced as spare parts. See Chapter 7 for
more details.
The ZG0391 power supply in Type 2825 is an FRP. To assure economical reuse, it is
important that no attempt is made to repair it locally. If such an attempt is made,
the price of an exchange FRP is 100% the price of a new one.
Therefore, DO NOT ATTEMPT ANY REPAIR to ZG0391. If a fault is found,
order an FRP under number FR0173.

Chapter 1 — General Information
Service Policy and FRP Number
Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
1−4

Acquisition Front-end Type 2825
Service Manual
BI5033–12e 2−1
Chapter 2
Service Note

Chapter 2 — Service Note
On-line Editions of the Service Manual
Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
2−2
2.1 On-line Editions of the Service Manual
Note: An on-line edition of a service manual is one that has not been published in printed
form. On-line manuals have the letter “e” appended to the literature number (“e”
denotes “electronic”).
From time to time some minor changes may be made to improve the performance
and serviceability of Type 2825. 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 when any are made.
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 2825. All information concerning these changes, or any
other changes to the Service manual, will be released in the form of a Service Note.
Note: Printed Service Notes are 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.

Acquisition Front-end Type 2825
Service Manual
BI5033–12e 3−1
Chapter 3
Checking Procedure

Chapter 3 — Checking Procedure
Introduction
Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
3−2
3.1 Introduction
The checking procedure is performed on a fully assembled Type 2825 (including
those modules normally inserted by the user). The procedure enables you to verify
that Type 2825 meets specifications. In the case of a fault appearing in Type 2825,
refer to Chapter 4 of this manual.
3.2 Checking Procedure
Warning: The checking procedure must only be done by trained service personnel as
hazardous voltages are exposed.
1. Remove the back panel
2. Check that the voltages on the backplane ZH0444 are as shown in Table 3.1:
Table 3.1 Measuring points and voltages on backplane ZH0444
3.3 Test of ventilator
If the ventilator is not moving, or moving slowly, gently heat the heat sensor on the
back panel through slot#0. This should make the fan rotate faster.
GND Point Measuring
Point Expected Voltage VTolerance ±V
X19–1 X19–2 +5.0 0.2
X19–7 X19–6 +5.0 0.1
X19–8
X19–3 +15.0 0.1
X19–5 –15.0 0.1
X18–1 +150 5
X18–2 +200 0.2
X18–3 –17.0 0.2
X18–5 +28 2
X19–1 X18–6 +15 1

Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
4−1
Chapter 4
Adjustment Procedure

Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
4−2
4.1 Introduction
The purpose of this procedure is to realign the power supply ZG0391 if it does not
fulfil the specifications stated in Chapter 3.
4.2 Procedure
Warning: The adjustment procedure must only be done by trained service personnel
as hazardous voltages are exposed.
1. Remove the power supply as described in Chapter 7
2. With the power supply on the workbench, re-connect all the cables except Taxi-
cable AQ1685 and Fan-cable AQ1682 (see Fig.4.1).
3. Turn on the power and set the voltages on ZG0391 as shown in Table 4.1,
working from the top of the table to the bottom.
Fig.4.1 Power-supply board ZG0391
970180e
AQ 1685
AQ 1682
Fan cable
AQ 1686
AQ 1636
AQ 1567

Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
4−3
Table 4.1 Measuring points, voltages and adjustment points on ZG0391.
GND
point Measuring point Expected voltage VTolerance ± VAdjustment point
J3 J2 +5.0 0.2 P6
J5 J9 pin 3 –17.0 0.2 P3
J6 –15.0 0.1 P2
J4 +15.0 0.1 P1
J9 pin 2 +200.0 0.2 P4
J9 pin 5 +28 2 P7
J8 J7 +5.0 0.2 P5

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Service Manual Brüel & Kjær
4−4

Acquisition Front-end Type 2825
Service Manual
BI5033–12e 5−1
Chapter 5
Troubleshooting

Chapter 5 — Troubleshooting
Introduction
Acquisition Front-end Type 2825
Service Manual Brüel & Kjær
5−2
5.1 Introduction
If the power supply voltages are not as indicated in Chapter 3, and they cannot be
corrected by using the adjustment procedure (Chapter 4), it is necessary to find the
defective module(s).
5.2 Procedure
1. Switch Power Off.
2. Remove all modules from Type 2825.
3. Switch Power On, and check if the voltages are correct according to Chapter 3.
If the voltages are correct, the problem must be on one of the modules. Re-insert
them one by one until you find the one that load the Power Supply.
If the voltages are incorrect, you must isolate the problem as described below:
1. Check that the automatic fuses are not tripped
2. Measure the mains voltage to see if it is correct
3. If the fuses are not tripped and the mains voltage is OK, the problem must be
in the Power Supply. Exchange the ZG0391 power supply.
5.3 Cooling fan
Gently heat the sensor mounted on the bottom of the power supply. The voltage on
J10, pin 1+2 should rise to lie between 12V and 14V. After the sensor has cooled,
gently heat the sensor mounted by slot#0. Again the voltage on J10, pin 1+2 should
rise to lie between 12V and 14V.