KERN EG 220-3NM, EW 420-3NM, EG 420-3NM, EW 620-3NM, EG 620-3NM Service Manual

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KERN & Sohn GmbH
Ziegelei 1 D-72336 Balingen-Frommern E-Mail: info@kern-sohn.com
Tel: 0049-[0]7433- 9933-0 Fax: 0049-[0]7433-9933-149 Internet: www.kern-sohn.com
GB
Service Manual
Electronic Precision Balances
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KERN EW · EW-C · EG (N)
Version 2.2 01/2007
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GB
KERN EW · EW-C · EG (N)
Version 2.2
Service Manual Electronic Precision Balances
1 TOTAL VIEW ..........................................................................................................4
1.1 Total View Of EW Type - 220-12000g........................................................ 4
1.2 Total View Of EG Type - 220-620g, 2200g, 4200g..................................... 4
1.3 Total View Of EW-C Type - 600ct (120g)................................................... 5
1.4 Total View Of EW Type - 120g/0,0002g..................................................... 5
2 ELECTRONIC CONSTRUCTION ...........................................................................6
2.1 Block Diagram.............................................................................................. 6
2.2 Whole Wiring................................................................................................ 7
3 TROUBLESHOOTING............................................................................................8
3.1 Troubleshooting Procedure.......................................................................... 8
3.2 Trouble shooting Table................................................................................. 9
3.3 Primary Checks.......................................................................................... 10
3.4 Checks For Electric/Electronic Parts.......................................................... 11
4 ADJUSTMENTS AND SETTINGS........................................................................12
4.1 Span Calibration (CAL) .............................................................................. 12
4.1.1 EW and EW-C Type............................................................................ 12
4.1.2 EG Type.............................................................................................. 13
4.2 Lock Switch................................................................................................ 14
4.3 Corner Error Adjustment ............................................................................ 15
4.3.1 EW – 120-1200 and EW-C Type......................................................... 15
4.3.2 EW 2200-12K................................................................................... 16
4.4 Adjustment Sequence For Cases............................................................... 17
4.5 Resetting Address Data (Coefficients) ...................................................... 18
4.6 How To Call Address Mode/How To Re-write Address Data ..................... 19
4.7 Linearity Adjustment................................................................................... 20
4.8 Calibration Of Built-In Weight (Ref Cal)...................................................... 23
5 PARTS REPLACEMENTS....................................................................................25
5.1 How to remove the case............................................................................. 25
5.1.1 EW 220-1200...................................................................................... 25
5.1.2 EW 2200-12K...................................................................................... 26
5.1.3 EW-C .................................................................................................. 27
5.1.4 EW 120-4 NM...................................................................................... 28
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5.2 How To Cover The Case............................................................................ 29
5.2.1 EW 120-1200 and EW-C..................................................................... 29
5.2.2 EW 2200-12K...................................................................................... 29
5.3 Sequence Of Mechanism Unit Replacement.............................................. 30
5.3.1 How To Remove The Weighing Mechanism Unit................................ 31
5.3.2 How To Install Weighing Mechanism.................................................. 33
5.4 Plate Rib Replacement............................................................................... 34
5.4.1 Plate Rib Replacement Procedure...................................................... 35
5.5 Sequence Of Tuning-Fork Sensor Replacement........................................ 36
5.5.1 How to uninstall Tuning-fork assy ....................................................... 36
5.6 Sequence Of The AJDP Circuit Board Replacement ................................. 37
5.6.1 How To Remove AJDP Circuit Board.................................................. 37
5.6.2 How To Install AJDP Circuit Board...................................................... 38
5.7 How To Remove Calibration Weight Unit................................................... 39
5.7.1 EG 220-620......................................................................................... 39
5.7.2 EG 2200-4200..................................................................................... 39
5.8 How To Install Calibration Weight Unit....................................................... 41
6 INSTALLATION OPTIONS...................................................................................42
6.1 Installation Of Battery Option ..................................................................... 42
6.1.1 EW 120-1200 and EW-C..................................................................... 42
6.1.2 EW 2200-12K...................................................................................... 43
7 PARTS LIST..........................................................................................................44
7.1 EW 220-1200 ............................................................................................. 44
7.2 EW 2200-12K............................................................................................. 45
7.3 EW-C / EW 120-4 NM................................................................................ 46
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1 Total View
1.1 Total View Of EW Type - 220-12000g
1.2 Total View Of EG Type - 220-620g, 2200g, 4200g
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1.3 Total View Of EW-C Type - 600ct (120g)
1.4 Total View Of EW Type - 120g/0,0002g
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2 Electronic Construction
2.1 Block Diagram
EG
EG
AC Adaptor
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2.2 Whole Wiring
EG
EG
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3 Troubleshooting
3.1 Troubleshooting Procedure
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3.2 Trouble shooting Table
Symptoms Causes & Remedy
No display lights on. 1. AJDP board is defective.
2. AC adapter is defective.
3. Wrong connection of connection c ords inside.
4. Built-in battery (option) is discharged.
u-Err
or
o-Err
appears self test of segments.
1. Wrong weighing pan is applied.
2. Tuning-fork sensor or mechanism unit is defective.
3. AJDP board is defective.
4. Setting of address data has mistake.
5. Coefficient memories (address data) have changed by noises or static electricity. Adjust linearity.
Display dose not get settled down.
Display dose not repeat correctly.
Zero point drifts.
1. Some parts such as stopper touches others.
2. Weighing pan touches other parts.
3. Foreign substance is in the scale.
4. Tuning-fork sensor or mechanism unit is defective.
5. Affected by a wind or disturbing oscillation. Check environment or working base. Check also setting of stabilization time. See operation manual.
o-Err
appears with a net load less than specified capacity (F.S. +9d).
1. Gross weight applied to the scale pan (net weight + tare value) exceeds the scale capacity.
2. Coefficient memories (address data) have changed by noises or static electricity. Adjust linearity.
3. Setting of address data has mistake.
4. Calibration weight is not correct.
Span is out of specified range.
1. Tuning-fork sensor or mechanism unit is defective.
2. AJDP board is defective.
3. Setting of address data has mistake.
4. Coefficient memories (address data) have changed by noises or static electricity.
Linearity is out of specified range.
1. Tuning-fork sensor or mechanism unit is defective.
2. Setting of address data has mistake.
3. Coefficient memories (address data) have changed by noises or static electricity.
4. Calibration weight is not correct.
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Symptoms Causes & Remedy
Corner error is too much. 1. Mechanism unit is defective, such as Roberval
plate (Spring) has been bent or twisted.
2. Pan base touches other parts. Display suddenly disappeared in operation.
1. Built-in battery (option) has been consumed.
2. AJDP board is defective.
3. AC adaptor is defective.
b-Err
appears.
1. AJDP board is defective.
2. Coefficient memories ( address data) have
changed by noises or static electricity. Adjust linearity.
d-Err
appears.
1. Address data related to determine the capacity
has been destroyed. Contact the shipper.
2. AJDP board is defective.
I-Err
appears.
1. The calibration weight is less than ½ F.S.
2-Err
appears.
1. The data error exceed s 0.4%. Or perhaps the
scale may be defective. Contact the shipper.
3.3 Primary Checks
1. Is any wind around the site?
Is any oscillation? Is the working table stable.
2. Is anything under the pan base or the weighing pan?
3. Is the weighing pan right one.
4. Is AC adaptor connected both with the scale and with the scale and with the outlet properly?
5. Is battery option charged sufficiently?
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3.4 Checks For Electric/Electronic Parts
-AJDP Circuit board-
Checks for electric/electronic parts are to be carried out on back of AJDP board after removing the upper case, at test Points and Pins of CN1, CN4, TP4 and TP6.
1. Check of input voltage
TP0 - (1) of CN1 •••••• +8V ~ +12V
2. Power voltage in the circuit
TP0 - (2) of CN4 •••••• +4,75V ~ +5,25V
3. Check of signal wav es (1)
TP0 - TP6
4. Check of signal wav es (2)
TP0 - TP4
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4 Adjustments and Settings
4.1 Span Calibration (CAL)
4.1.1 EW and EW-C Type
1. It is recommended to use a calibration weight of better accuracy than the scale.
2. The calibration is available with ½ of F.S. Nevertheless, it is recommend to use weight closer to F.S. for accurate calibration.
3. Error messages:
o-Err
: The calibration weight is over the full capacity.
I-Err
: The calibration weight is less than ½ of the capacity.
2-Err
: The data error exceeds 1%. Or perhaps the scale may be defective.
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4.1.2 EG Type
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4.2 Lock Switch
Set the lock switch to “Locked” before stamping or sealing so that the user is unable to change parameters or to calibrate the scale.
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4.3 Corner Error Adjustment
4.3.1 EW – 120-1200 and EW-C Type
Remove the case referring to 5 – 1. Place the pan base, then place the weighing pan on the mechanism. Adjust the level.
Remove fixing screw on AJDP board and unplug connector with CN4 on AJDP board. Adjust corner errors by adjusting bolts referring to following illustrations.
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4.3.2 EW – 2200-12K
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4.4 Adjustment Sequence For Cases
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4.5 Resetting Address Data (Coefficients)
When memories of address data are changed or lost by some reasons, such as by replacement of PCB, or by noises or static electricity, re-set original data by following procedure.
1. Location Of Original Data
2. Contents Of Data Sheet
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4.6 How To Call Address Mode/How To Re-write Address Data
EW-C Type
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4.7 Linearity Adjustment
1. How To Adjust Linearity
EW -C Type
EG type
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2. Table Increasing Calibration Weight For Linearity Adjustment
( ) : Cumulative total of weights on the scale Model Display
EW 220-3NM EG 220-3NM
EW 420-3NM EG 420-3NM
EW 620-3NM EG 620-3NM
EW 820-3NM
on =
0g
(0g)
0g
(0g)
0g
(0g)
0g
(0g)
on 1
50g
(50g)
100g
(100g)
150g
(150g)
200g
(200g)
on 2
50g
(100g)
100g
(200g)
150g
(300g)
200g
(400g)
on 3
50g
(150g)
100g
(300g)
150g
(450g)
200g
(600g)
on 4
70g
(220g)
120g
(420g)
170g
(620g)
220g
(820g)
Calibration
Weight
Required
50g x 4
20g x1
100g x 4
20g x 1
100g x 4
50g x 4 20g x 1
200g x 4
20g x 1
Model Display
EW 2200-2NM EG 2200-2NM
EW 4200-2NM EG 4200-2NM
EW 6200-2NM EW12000-1NM
on 0
0g
(0g)
0g
(0g)
0g
(0g)
0g
(0g)
on 1
500g
(500g)
1kg
(1000g)
1,5kg
(1500g)
3kg
(3000g)
on 2
500g
(1000g)
1kg
(2000g)
1,5kg
(3000g)
3kg
(6000g)
on 3
500g
(1500g)
1kg
(3000g)
1,5kg
(4500g)
3kg
(9000g)
on 4
700g
(2200g)
1,2kg
(4200g)
1,7kg
(6200g)
3kg
(12000g)
Calibration
Weight
Required
500g x 4 200g x 1
1kg x 4
200g x 1
1kg x 4 500g x 4 200g x 1
2kg x 4 1kg x 4
Please use the weight for F1 (OIML R – 111) or higher class to maintain the accuracy.
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( ) : Cumulative total of weights on the scale
Model Display
EW 600-C3 NM EW 120-4 NM
on 0
0g
(0g)
0g
(0g)
on 1
30g
(30g)
30g
(30g)
on 2
30g
(60g)
30g
(60g)
on 3
30g
(90g)
30g
(90g)
on 4
30g
(120g)
30g
(120g)
Calibration
Weight
Required
20g x 4 10g x 4
20g x 4
10g x 4
Please use the weight for E2 (OIML R – 111) or higher class to maintain the
accuracy.
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4.8 Calibration Of Built-In Weight (Ref Cal)
- EG Type -
Following does not describe the procedure of ordinary span calibration.
This is the procedure of calibration of the built-in weight with EG scales
It is necessary to adjust the linearity of the scale beforehand. Refer to 4-7.
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Cautions
(1) [ ] must be carried out in following cases:
(1) When built-in weight is added or replaced. (2) When linearity adjustment is done. (3) When AJDP board is replaced.
(2) The quality/tolerance of the reference weight determine the accuracy of the scale. Use weights of higher accuracy than the scale.
(3) Adjust the level beforehand. The REF CAL must be done in a good environment, no wind, no oscillation, and no temperature changes. (4) : The reference weight is less than ½ of F.S. : The data error exceeds 1%. Adjust the linearity.
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5 Parts Replacements
5.1 How to remove the case
5.1.1 EW 220-1200
(1) Unplug the AC adaptor. Remove the pan and pan base.
(2) Remove case fixing screw with a screwdriver. (3) Locate two hooks beneath the scale near front. Pull those
two hooks toward you to lift the case up, then shift the case to rear to release it from hooks.
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5.1.2 EW 2200-12K
(1) Remove the weighing. (2) Remove case fixing screw with a (+) screwdriver.(2 places in
the top and 1 place in the chassis)
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5.1.3 EW-C
(1) Unplug the AC adaptor. Remove the pan and pan base. (2) Remove case fixing screw with screwdriver. (3) Locate two hooks toward you to lift the case up, then shift the
case to rear to release it from hooks.
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5.1.4 EW 120-4 NM
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5.2 How To Cover The Case
5.2.1 EW 120-1200 and EW-C
(1) Cover the scale with the case, seeing cables are just stored inside
properly. Insert the rear hooks first, then press the upper case gently
until two front hooks are set securely. (2) Drive in case fixing screw securely. (3) Set pan base and then weighing pan on the scale.
5.2.2 EW 2200-12K
(1) Put the case on properly catching connection codes. (2) Insert the case fixing screw with a (+) screwdriver. (2 places in top and
1 place in the chassis). (3) Install the pan base and put the weighing pan on.
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5.3 Sequence Of Mechanism Unit Replacement
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5.3.1 How To Remove The Weighing Mechanism Unit
5.3.1.1 EW 120-1200 and EW-C
(1) Remove the case referring to 5-1. (2) Remove four sensor cover fixing screw. (3) Remove wires to the tuning-fork sensor, by welding solders at AJDP
circuit board (4) Remove the AJDP circuit board fixing screw.
AJDP Circuit Board Fixing Screw
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* For EG series (With-internal-calibration type), refer to section 5-6.
(5) Remove three mechanism unit screws. (6) Remove the mechanism unit by holding the chassis.
Mechanism unit fixing screws
5.3.1.2 EW 2200-12K
(1) Remove the case referring to 5-1. (2) Remove wires to the Tuning-fork sensor, by welding solders at AJDP
circuit board. (3) Remove the AJDP circuit board fixing screw and AJDP circuit board.
AJDP Circuit Board Fixing Screws
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* For EG series (With-internal-calibration type), refer to section 5-6.
(4) Remove four mechanism unit fixing screws (5) Remove (cut) the board band. (6) Remove the mechanism unit by holding at the chassis.
 
5.3.2 How To Install Weighing Mechanism
(1) Place the mechanism on the chassis. Fit it with the fixing screws. (2) Solder wires of the Tuning-fork sensor to the AJDP circuit board. (3) (1)Cover the mechanism unite with the sensor cover. Fit it with four
fixing screw. (EW 120-1200).
(2)Fix the Tuning-fork sensor wire to hexagon pillar with cord
band. (EW2200-12K) (4) Cover the scale referring to 5-2.
Circuit Board Fixing Screw
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5.4 Plate Rib Replacement
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5.4.1 Plate Rib Replacement Procedure
(1) Remove the mechanism unit from the chassis. (5-3) (2) Replace the tuning-fork sensor. (3) Attach the fixing jig with fixing screws for the tuning-fork sensor assy. *The fixing jig should be attacked to the guide link. (4) Remove the damaged plate rib by unscrewing and fix the new one. (5) Remove the fixing jig. (6) Fix the tuning-fork sensor assy. (torque 20kgfcm)
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5.5 Sequence Of Tuning-Fork Sensor Replacement
5.5.1 How to uninstall Tuning-fork assy
(1) Remove the mechanical unit from the chassis. (2) Replace the tuning-fork sensor. (3) Insert shim at stopper. (4) While holding guide link down to under direction, tighten screws. (Need the torque 25kgfcm)
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5.6 Sequence Of The AJDP Circuit Board Replacement
5.6.1 How To Remove AJDP Circuit Board
(1) Remove the case referring to 5-1. (2) Remove wires to the Tuning-fork sensor, by welding solders at AJDP
circuit board. (3) Remove the AJDP circuit board fixing screw. (4) Unplug connectors at CN1, CN4, (and CN3 with AJH-CE) on AJDP
board. With battery option, unplug CN5, in addition.
Circuit Board Fixing Screw
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5.6.2 How To Install AJDP Circuit Board
(1) Solder wires of the Tuning-fork sensor to the new AJDP board (2) Plug connectors. CN1 : AJLF cord CN3 : Calibration cord CN4 : AJIF cord CN5 : Battery cord (3) Place the AJDP board on the chassis. Fix it with a fixing screw. (4) Cover the scale referring to 5-2.
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5.7 How To Remove Calibration Weight Unit
5.7.1 EG 220-620
1. Remove the CN3 connector. (Removing AJDP P.C.B. in advance makes it easy to do it.)
2. Remove (cut) the cord band.
3. Unscrew at two points.
5.7.2 EG 2200-4200
(1) Remove SW cord assy from AJDP circuit board
(2) Remove the weight holder
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Weight Holder
(3) Remove the side ring and disassemble the weight
Weight Fixing Screw Side Ring
(4) Remove the weight shaft from the mechanical main unit
Weight Shaft
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5.8 How To Install Calibration Weight Unit
Follow the instruction in 5-7 by the opposite order. Refer to the position for the installation below.
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6 Installation Options
6.1 Installation Of Battery Option
6.1.1 EW 120-1200 and EW-C
(1) Remove the case referring to 5-1. (2) Plug AJ battery cord to CN5 on AJDP board. (3) Install AJ battery holder assy.
(4) Cover the scale and stick battery label above power jack on the rear panel.
Battery Label
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6.1.2 EW 2200-12K
(1) Remove the case referring to 5-1. (2) Plug AJ battery cord to CN5 on AJDP board. (3) Fasten the AJM battery held together into the nylon-clamp which has holed the
cord of the AJMIF circuit board assy.
Nylon Clamp
AJMBT Assy
(4) Cover the scale and stick the battery label above power jack on the rear panel.
Battery Label
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7 Parts List
7.1 EW 220-1200
EW 220/-420/-620 EG 220/-420/-620
EW 820/-1200
EG 220/-420/-620
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7.2 EW 2200-12K
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7.3 EW-C / EW 120-4 NM
EW 600-C3 NM EW 120-4 NM
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