KERN & Sohn GmbH
Ziegelei 1
D-72336 Balingen
E-Mail: info@kern-sohn.com
Tel: +49-[0]7433- 9933-0
Fax: +49-[0]7433-9933-149
Internet: www.kern-sohn.com
Service manual
Analytical balances
KERN AEJ/AES
Version 1.0
4/2009
GB
AEJ/AES-SH-e-0910
1
GB
KERN AEJ/AES
Version 1.0 4/2009
Service manual
Analytical balances
Table of Contents
1 Basic information.............................................................................................. 3
2 Total View........................................................................................................... 4
3 Electric/Electronic Construction......................................................................5
3.1 Block Diagram ........................................................................................................5
3.2 Whole Wiring...........................................................................................................6
4 Troubleshooting................................................................................................ 7
4.1 Troubleshooting Procedure...................................................................................7
4.2 Troubleshooting Table...........................................................................................8
4.3 Primary Check.......................................................................................................10
4.4 Check of Electric/Electronic Parts......................................................................11
5 Adjustment and Setting.................................................................................. 13
5.1 Span Calibration (Adjustment with internal weight – AEJ) ..............................13
5.2 Span Calibration (Adjustment with external weight – AES).............................14
5.3 Verification switch and seals ..............................................................................15
5.4 Corner Error Adjustment .....................................................................................16
5.5 Linearity Adjustment............................................................................................17
5.5.1 Linearity Adjustment of AES 120-4 and AEJ 120-4M...................................................... 17
5.5.2 Linearity Adjustment of AES 220-4 and AEJ 220-4M...................................................... 18
5.6 Calibration of Built-In Weight (Ref Cal) – only AEJ...........................................19
5.7 Address Data Check and Re-setting...................................................................20
5.8 Adjustment of Overload Stopper ........................................................................22
6 Parts Replacement.......................................................................................... 23
6.1 How to Remove the Case.....................................................................................23
6.2 The Sequence of HT-DP Board Replacement....................................................24
6.3 The Sequence of Mechanical Unit Replacement...............................................26
6.4 The Sequence of Tuning-Fork Sensor................................................................29
7 Parts List.......................................................................................................... 30
7.1 Explosion Diagram...............................................................................................30
7.2 Bill of Material.......................................................................................................31
8 Appendix.......................................................................................................... 32
2
1 Basic information
Grundlegende Hinweise
The device must be repaired only by trained specialist staff or personnel with
professional formation (such as a repair-specialist accredited by law
concerning verification).
The service manual is obligatory for repair work.
After repair, original conditions of the device have to be restored.
Only original spare parts should be used.
Instructions about conformity-evaluated scales
:
Repair must be carried only at 100% compliance with the type approval.
A violation of this specification will result in a loss of the type approval!
After successful repair the balance will have to be reverified before it can be
used again in a statutorily regulated field.
Das Gerät darf nur von geschultem oder beruflich ausgebildetem
Fachpersonal (z. B. eichrechtlich anerkannter Instandsetzer) repariert werden.
Die Serviceanleitung ist bindend für Reparaturen.
Das Gerät muss nach erfolgter Reparatur wieder in den Originalzustand
zurückversetzt werden.
Es dürfen nur Originalersatzteile verwendet werden.
Hinweis zu konformitätsbewerteten Waagen:
Reparatur darf nur in 100% -iger Übereinstimmung mit der
Bauartzulassung erfolgen. Ein Verstoß gegen diese Vorgabe führt zum Erlöschen
der Bauartzulassung!
Nach erfolgreicher Reparatur muss eine Nacheichung erfolgen, um die Waage
wieder im gesetzlich geregelten Bereich verwenden zu können.
3
2 Total View
Windshield
Weighing plate
Protection ring
Air bubble
LCD display
RS 232 interface
Printer interface
Connection mains adapter
Foot screw
Underfloor
weighing device
Foot
4
3 Electric/Electronic Construction
3.1 Block Diagram
Calibration Weight Unit
(AEJ only)
PRINT
5
3.2 Whole Wiring
Calibration Weight Unit
(AEJ only)
PRINT
6
4 Troubleshooting
4.1 Troubleshooting Procedure
7
4.2 Troubleshooting Table
SYMPTOMS CAUSES & REMEDY
No display lights on.
1. HT-DP board is defective.
2. AC adaptor is defective.
3. Inner connecting cord is not properly connected.
[
u - Err ] or [ o - Err ] appears
on the display.
1. Wrong weighing pan is applied.
2. Tuning-fork sensor or mechanical unit is
defective.
3. HT-DP board is defective.
4. Setting of address data has mistake.
5. Coefficient memories (address data) have
changed by noise or static electricity. Re-set the
address data and/or adjust the linearity.
Display does not get settled down.
Display does not repeat correctly.
Zero point drifts.
1. Some parts such as stopper touch others.
2. Weighing pan touch other parts.
3. Foreign substances are in the scale.
4. Tuning-fork sensor or mechanical unit is
defective.
5. Affected by wind or disturbing oscillation.
[
o - Err ]
appears with net load less
than
full capacity.
1. Gross weight applied to the scale pan (net weight
+ tare value) exceeds the scale capacity.
2. Setting of address data has mistake.
3. Coefficient memories (address data) have
changed by noise or static electricity. Re-set the
address data and/or adjust the linearity.
4. Wrong external weight is used in the span
calibration.
Span error is too much.
1. Tuning-fork sensor or mechanical unit is
defective.
2. HT-DP board is defective.
3. Setting of address data has mistake.
4. Coefficient memories (address data) have
changed by noise or static electricity. Re-set the
address data and/or adjust the linearity.
Non-linearity is too much.
1. Tuning-fork sensor or mechanical unit is
defective.
2. Setting of address data has mistake.
3. Coefficient memories (address data) have
changed by noises or static electricity. Re-set the
address data and/or adjust the linearity.
4. Wrong external weight is used in span
calibration.
8
SYMPTOMS CAUSES & REMEDY
Corner Error is too much.
1. Mechanical unit is defective. Leaf spring is bent
or twisted.
2. Pan base touch other parts.
Display suddenly disappeared.
1. HT-DP board is defective.
2. AC adaptor is defective.
or
appears.
1. HT-DP board is defective.
2. Coefficient memories (address data) have
changed by noises or static electricity. Re-set the
address data and/or adjust the linearity.
appears.
1. The weight of reference sample is too light (%
mode, counting mode).
appears.
1. Wrong external weight is used in span calibration
(external weight must be more than 50% of
scale capacity).
appears.
1. Span error exceeds 1% of scale capacity in
span calibration. Check the external weight.
appears.
1. During calibration there was a weight on the
weighing plate. Remove it from the pan.
appears.
1. Span error exceeds 1% of capacity in automatic
span calibration.
appears.
1. Interval time is not properly set.
appears.
1. Internal clock is defective. Check internal clock
and replace HT-DP board, if necessary.
[
r - Err ] appears.
1. The weight error exceeds ±100.00mg. Re-set the
weight error within ±100.00mg
[
A - Err ] appears.
1. Internal calibration automatics defective
appears.
1. Wrong operation in Cumulate Function or Net
Addition Function.
9
4.3 Primary Check
1. Is there any wind around the site? Is there any oscillation?
2. Is anything under the pan base or the weighing pan?
balance nor under pan/pan base.
When you attach or remove pan,
pan base, windshield, take care no
dust and/or liquid gets into the
Pan base
Pan
3. Is the weighing pan the right one?
4. Is the windshield properly attached?
5. Is the working table stable?
6. Is the balance installed in level?
Position of the air
bubble in the level
Adjuster
7. Is the AC adaptor properly connected both with scale and with outlet?
AC adapter connector
10
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