Service manual

ManualsBrandsMitsubishi ManualsDomestic AppliancesMSC-GA20VB

CONTENTS

1. TECHNICAL CHANGES ····································2

2. PART NAMES AND FUNCTIONS······················3

3. SPECIFICATION·················································3

4. NOISE CRITERIA CURVES·······························5

5. OUTLINES AND DIMENSIONS ·························6

6. WIRING DIAGRAM ············································7

7. REFRIGERANT SYSTEM DIAGRAM················8

8. PERFORMANCE CURVES································9

9. ACTUATOR CONTROL····································19

10. SERVICE FUNCTIONS·····································20

11. TROUBLESHOOTING······································20

12. DISASSEMBLY INSTRUCTIONS·····················27

13. PARTS LIST······················································30

14. RoHS PARTS LIST···········································32

HFC

utilized

R410A

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

MUH-GA20VB

MUH-GA25VB

MUH-GA35VB

Wireless type

Models

MUH-GA20VB-

MUH-GA25VB-

MUH-GA35VB-

SERVICE MANUAL

OUTDOOR UNIT

Indoor unit service manual

MSC-GA• VB Series (OB385)

MSC-CA• VB Series (OB393)

MSC-CB• VB Series (OB439)

No. OB387

REVISED EDITION-B

Please void OB387 REVISED EDITION-A.

Revision B:

● MUH-GA35VB - has been added.

NOTE:

• This service manual describes technical data of outdoor units.

• RoHS compliant products have <G> mark on the spec name plate.

For servicing of RoHS compliant products, refer to the RoHS Parts List.

OB387B-1.qxp 07.5.23 2:47 PM Page 1

Summary of content (36 pages)

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OB387B-1.qxp 07.5.23 2:47 PM Page 1 Revision B: ● MUH-GA35VB - SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS E3 has been added. Please void OB387 REVISED EDITION-A. OUTDOOR UNIT SERVICE MANUAL HFC utilized No. OB387 REVISED EDITION-B R410A Wireless type Models MUH-GA20VBMUH-GA20VBMUH-GA25VBMUH-GA25VBMUH-GA35VBMUH-GA35VB- E1 E2 E1 E2 E1 E3 Indoor unit service manual MSC-GA• VB Series (OB385) MSC-CA• VB Series (OB393) MSC-CB• VB Series (OB439) CONTENTS MUH-GA20VB MUH-GA25VB MUH-GA35VB 1.
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OB387B-1.qxp 07.5.23 2:47 PM Page 2 Revision A: • MUH-GA20VB- E2 and MUH-GA25VB- E3 has been added. E2 have been added. Revision B: • MUH-GA35VB- 1 TECHNICAL CHANGES MUH-A07YV- E1 ➔MUH-GA20VB- E1 1. 2. 3. 4. 5. 6. 7. Indication of capacity has been changed. (BTU base ➔ kw) Dimension of outdoor unit has been changed. (W780mm x H540mm x D255mm ➔ W800mm x H550mm x D285mm) Stop valve cover has been added. Outdoor fan motor has been changed.
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OB387B-1.qxp 07.5.
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OB387B-1.qxp 07.5.23 2:48 PM Page 4 MUH-GA25VB - E1 Single phase 230V,50Hz Cooling Heating 2.65 3.0 1.1 — 1,902 10 3.43 3.43 785 785 — 100 100 22 3.10 3.10 0.33 3.23 3.66 RN104VHSHT 700 C-R 3.40 C-S 4.56 RA6V33-KB WHT-BLK 215 BLK-RED 307 800o550o285 MUH-GA25VB - E2 Single phase 230V,50Hz Cooling Heating 2.65 3.0 1.1 — 1,902 10 3.43 3.43 785 785 — 100 100 19 3.10 3.10 0.33 3.23 3.66 KN104VTMHC 700 C-R 3.62 C-S 5.
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07.5.23 2:48 PM Page 5 NOISE CRITERIA CURVES 4 MUH-GA20VB FUNCTION SPL(dB(A)) MUH-GA25VB MUH-GA35VB LINE COOLING HEATING 47 Test conditions, Cooling :DB35: Heating :DB 7: 90 COOLING SPL(dB(A)) LINE 49 HEATING Test conditions, Cooling :DB35: Heating :DB 7: WB24: WB 6: 90 80 70 NC-70 60 NC-60 50 NC-50 40 NC-40 30 NC-30 20 FUNCTION WB24: WB 6: OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR OB387B-1.
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OB387B-1.qxp 07.5.23 2:48 PM 5 Page 6 OUTLINES AND DIMENSIONS MUH-GA20VB MUH-GA25VB MUH-GA35VB Unit: mm OUTDOOR UNIT REQUIRED SPACE Basically open 100mm or more without any obstruction in front and on both sides of the unit. ore mm or m Bolt pitch for installation 304~325 ore 44 Air in (MUH-GA25 /GA35VB) 40 2 holes 10X21 e mm 200 or or m Open two sides of left, right, or rear side. 17.5 Service panel Air out 23 22.3 Liquid refrigerant pipe joint Refrigerant pipe (flared) [6.
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OB387B-1.qxp 07.5.
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OB387B-1.qxp 7 07.5.23 2:48 PM Page 8 REFRIGERANT SYSTEM DIAGRAM Unit:mm MUH-GA20VB MUH-GA25VB MUH-GA35VB- E1 OUTDOOR UNIT Refrigerant pipe [ 9.52 (with heat insulator) Flared connection 4-way valve Stop valve (with service port) Muffler Compressor Capillary tube [3.0x[1.4x700 (MUH-GA20VB [3.0x[1.4x900 (MUH-GA20VB [3.0x[1.4x1000(MUH-GA25VB [3.0x[1.6x1500(MUH-GA25VB [3.0x[1.4x500 (MUH-GA35VB Check valve Strainer #100 Flared connection Stop valve Capillary tube [3.0x[1.4x500 Refrigerant pipe [6.
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OB387B-1.qxp 07.5.23 2:48 PM Page 9 MAX. REFRIGERANT PIPING LENGTH Refrigerant piping : m Max. length A Model MUH-GA20VB Max. height B Piping size O.D : mm Gas Length of connecting pipe : m Liquid Indoor unit Outdoor unit Gas 0.43 Gas 0 Liquid 0.5 Liquid 0 20 MUH-GA25VB 10 MUH-GA35VB 9.52 6.35 25 MAX. HEIGHT DIFFERENCE Indoor unit Refrigerant Piping Max. length A Max.
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OB387B-1.qxp 07.5.23 2:48 PM Page 10 How to measure the indoor air wet-bulb/dry-bulb temperature difference 1. 2. 3. 4. 5. 6. 7. Attach at least 2 sets of wet-and dry-bulb thermometers to the indoor air intake as shown in the figure, and at least 2 sets of wet-and dry-bulb thermometers to the indoor air outlet. The thermometers must be attached to the position where air speed is high. Attach at least 2 sets of wet-and dry-bulb thermometers to the outdoor air intake.
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OB387B-1.qxp 07.5.23 2:48 PM Page 11 8-2.OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT COOL operation ➁ ③ Both indoor and outdoor unit are under the same temperature/humidity condition. Dry-bulb temperature Relative humidity(%) 20 50 25 60 30 70 Air flow should be set at MAX. The unit of pressure has been changed to MPa on the international system of units(SI unit system). f[Gauge] ) The conversion factor is : 1(MPa[Gauge]) =10.2(kgf/f Outdoor low pressure (kgf/F[Gauge])(MPa[Gauge]) 13 1.
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OB387B-1.qxp 07.5.23 2:48 PM Page 12 HEAT operation Outdoor:Dry bulb temperature 7,15,20°C Wet bulb temperature 6,12,14.5°C Condition indoor:Dry bulb temperature 20.0°C Wet bulb temperature 14.
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OB387B-1.qxp 07.5.23 2:48 PM Page 13 PERFORMANCE DATA COOL operation (230V) MSC-GA20VB : MUH-GA20VB CAPACITY : 2.3(kW) SHF : 0.74 INPUT : 715(W) 21 INDOOR INDOOR Q SHC SHF INPUT DB(:) WB(:) 21 18 2.70 1.51 0.56 572 21 20 2.82 1.24 0.44 601 22 18 2.70 1.62 0.60 572 22 20 2.82 1.35 0.48 601 22 22 2.93 1.06 0.36 622 23 18 2.70 1.73 0.64 572 23 20 2.82 1.47 0.52 601 23 22 2.93 1.17 0.40 622 24 18 2.70 1.84 0.68 572 24 20 2.82 1.58 0.56 601 24 22 2.93 1.29 0.44 622 24 24 3.08 0.99 0.32 651 25 18 2.70 1.
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OB387B-1.qxp 07.5.23 2:48 PM Page 14 PERFORMANCE DATA COOL operation (230V) MSC-GA20VB : MUH-GA20VB CAPACITY : 2.3(kW) SHF : 0.74 INPUT : 715(W) OUTDOOR DB(:) 35 40 INDOOR INDOOR DB(:) WB(:) Q SHC SHF INPUT Q SHC SHF INPUT Q 21 18 2.25 1.26 0.56 701 2.07 1.16 0.56 744 1.99 21 20 2.37 1.04 0.44 729 2.21 0.97 0.44 765 2.13 22 18 2.25 1.35 0.60 701 2.07 1.24 0.60 744 1.99 22 20 2.37 1.14 0.48 729 2.21 1.06 0.48 765 2.13 22 22 2.51 0.90 0.36 758 2.35 0.84 0.36 801 2.27 23 18 2.25 1.44 0.64 701 2.07 1.
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OB387B-1.qxp 07.5.23 2:48 PM Page 15 PERFORMANCE DATA COOL operation (230V) MSC-GA25VB : MUH-GA25VB CAPACITY : 2.65(kW) SHF : 0.70 INPUT : 820(W) OUTDOOR DB(:) 21 25 27 INDOOR INDOOR DB(:) WB(:) Q SHC SHF INPUT Q SHC SHF INPUT Q SHC SHF INPUT Q 21 18 3.11 1.62 0.52 656 2.98 1.55 0.52 689 2.86 1.49 0.52 722 2.76 21 20 3.25 1.30 0.40 689 3.11 1.25 0.40 730 3.02 1.21 0.40 746 2.92 22 18 3.11 1.74 0.56 656 2.98 1.67 0.56 689 2.86 1.60 0.56 722 2.76 22 20 3.25 1.43 0.44 689 3.11 1.37 0.44 730 3.02 1.
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OB387B-1.qxp 07.5.23 2:48 PM Page 16 PERFORMANCE DATA COOL operation (230V) MSC-GA25VB : MUH-GA25VB CAPACITY : 2.65(kW) SHF : 0.70 INDOOR INDOOR DB(:) WB(:) 21 21 22 22 22 23 23 23 24 24 24 24 25 25 25 25 26 26 26 26 26 27 27 27 27 27 28 28 28 28 28 29 29 29 29 29 30 30 30 30 30 31 31 31 31 31 32 32 32 32 32 NOTE Q INPUT : 820(W) OUTDOOR DB(:) 35 40 SHC SHF INPUT Q SHC SHF INPUT 18 2.60 1.35 0.52 804 20 2.73 1.09 0.40 836 18 2.60 1.45 0.56 804 20 2.73 1.20 0.44 836 22 2.89 0.92 0.32 869 18 2.60 1.
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OB387B-1.qxp 07.5.23 2:48 PM Page 17 PERFORMANCE DATA COOL operation (230V) MSC-GA35VB : MUH-GA35VB CAPACITY : 3.5(kW) SHF : 0.66 INDOOR INDOOR DB(:) WB(:) 21 18 21 20 22 18 22 20 22 22 23 18 23 20 23 22 24 18 24 20 24 22 24 24 25 18 25 20 25 22 25 24 26 18 26 20 26 22 26 24 26 26 27 18 27 20 27 22 27 24 27 26 28 18 28 20 28 22 28 24 28 26 29 18 29 20 29 22 29 24 29 26 30 18 30 20 30 22 30 24 30 26 31 18 31 20 31 22 31 24 31 26 32 18 32 20 32 22 32 24 32 26 NOTE Q 4.11 4.29 4.11 4.29 4.46 4.11 4.
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OB387B-1.qxp 07.5.23 2:48 PM Page 18 PERFORMANCE DATA COOL operation (230V) MSC-GA35VB : MUH-GA35VB CAPACITY : 3.5(kW) SHF : 0.66 INPUT : 1090(W) OUTDOOR DB(:) 35 40 INDOOR INDOOR DB(:) WB(:) Q SHC SHF INPUT Q SHC SHF INPUT Q 21 18 3.43 1.65 0.48 1068 3.15 1.51 0.48 1134 3.03 21 20 3.61 1.30 0.36 1112 3.36 1.21 0.36 1166 3.24 22 18 3.43 1.78 0.52 1068 3.15 1.64 0.52 1134 3.03 22 20 3.61 1.44 0.40 1112 3.36 1.34 0.40 1166 3.24 22 22 3.82 1.07 0.28 1155 3.57 1.00 0.28 1221 3.45 23 18 3.43 1.92 0.
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OB387B-1.qxp 07.5.23 2:48 PM Page 19 PERFORMANCE DATA HEAT operation (230V) MSC-GA20VB : MUH-GA20VB CAPACITY : 2.5(kW) INPUT : 690(W) OUTDOOR WB(:) INDOOR -10 -5 0 5 10 15 20 DB(:) Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT Q INPUT 3.50 731 2.88 697 3.18 718 2.23 607 2.55 656 1.58 449 1.90 538 15 3.36 766 2.75 718 3.05 738 2.13 635 2.43 683 1.50 483 1.80 573 21 3.25 794 2.63 752 2.93 773 1.98 669 2.30 718 1.35 518 1.68 607 26 MSC-GA25VB : MUH-GA25VB CAPACITY : 3.
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OB387B-1.qxp 10 07.5.23 2:48 PM Page 20 SERVICE FUNCTIONS MUH-GA20VB MUH-GA25VB MUH-GA35VB 10-1. COMPULSORY DEFROSTING MODE FOR SERVICE By short circuit of the connector JPDS and JPSG on the outdoor deicer P.C. board, defrosting mode can be accomplished regardless of the defrost interval restriction. (Refer to 11-5.) Defrost thermistor RT61 must read below -3°C. 10-2. CHANGE IN DEFROST SETTING When the JRF wire of the deicer P.C. board is cut, the defrost interval time will be changed.
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OB387B-1.qxp 07.5.23 2:48 PM Page 21 11-2. Instruction of troubleshooting MUH-GA20VB MUH-GA25VB MUH-GA35VB Start Indoor unit operates. Outdoor unit doesn't operate normally. Indoor unit operates. Outdoor unit doesn't operate. Outdoor unit operates in only Test Run operation. W Outdoor unit doesn't operate even in Test Run operation. W Check room Refer to 11-4. temperature A "Check of thermistor. outdoor unit". Refer to 11-5. "Test point diagram and voltage".
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OB387B-1.qxp 07.5.23 2:48 PM Page 22 11-3. Trouble criterion of main parts MUH-GA20VB MUH-GA25VB MUH-GA35VB Figure Check method and criterion Part name Measure the resistance with a tester. (Part temperature –10°C ~ 40°C) Defrost thermistor (RT63) Refer to 11-5. “Test point diagram and voltage”, “Outdoor deicer P.C. board”, the chart of thermistor. Compressor (MC) INNER PROTECTOR MUHGA20/GA25VB- Measure the resistance between the terminals with a tester.
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OB387B-1.qxp 07.5.23 2:48 PM Page 23 Compressor and/or outdoor fan motor doesn’t stop. B Check of outdoor unit Start Turn OFF the power supply. After 1 minute, turn ON power supply again. No Does compressor stop? Yes OK No Rectify the connecting wire. Replace the deicer P.C. board. No Does outdoor fan motor stop? Is there 230V AC between 3 on the compressor contactor (52C) and N on the outdoor terminal block (TB1)? Yes Replace the deicer P.C. board.
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OB387B-1.qxp 07.5.23 2:48 PM Page 24 When OPERATION INDICATOR lamp flashes 0.5-second intervals. Outdoor unit does not operate. D How to check mis-wiring and serial signal error w 1 Set the switch(SW2-2) on indoor electronic control P.C. board to MU or MUX type, when the outdoor unit is MU or MUX type. If the setting is MUH or MXZ type, the unit does not work. Start w 2 Short circuit of JPG and JPS on the indoor electronic control P.C. board enables self-check to be displayed in 3 seconds.
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OB387B-1.qxp 07.5.23 2:48 PM Page 25 When OPERATION INDICATOR lamp flashes 6-time. Thermistors in the outdoor unit are abnormal. E Check of outdoor thermistor Start Replace the deicer P.C. board. Defrost thermistor (RT61) Turn OFF the power supply. Measure resistance between CN 661 1 and 2. Is the resistance of thermistor normal? Yes Reconnect CN661. Turn ON the power supply and press the EMERGENCY OPERATION switch.
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OB387B-1.qxp 07.5.23 2:48 PM Page 26 11-5. Test point diagram and voltage Power supply input 230V AC } } CN711 CN721 Outdoor fan motor R.V. coil 230V AC 230V AC } MUH-GA20VB MUH-GA25VB MUH-GA35VB Outdoor deicer P.C. board NR61 Varistor F61 Fuse 2A/250V + -- } CN661 1-2 Defrost thermistor RT61 12V DC J204 + J101 -- 26 R601 5~10VDC Defrost interval time short pin (JPDS, JPSG) (Refer to 10-1.) Jumper wire for change in defrost setting (JRF,JRG) (Refer to 10-2.
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OB387B-1.qxp 07.5.23 2:48 PM 12 Page 27 DISASSEMBLY INSTRUCTIONS <"Terminal with locking mechanism" Detaching points> The terminal which has the locking mechanism can be detached as shown below. There are two types ( Refer to (1) and (2)) of the terminal with locking mechanism. The terminal without locking mechanism can be detached by pulling it out. Check the shape of the terminal before detaching. (1) Slide the sleeve and check if there is a locking lever or not.
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OB387B-1.qxp 07.5.23 2:48 PM Page 28 OPERATING PROCEDURE PHOTOS 2. Removing the deicer P.C. board Photo 4 (1) Remove the service panel and the cabinet. (2) Disconnect all the connectors and the terminals on the deicer P.C. board. (3) Remove the deicer P.C. board. Screw of the Deicer relay panel P.C. board Relay panel Terminal block Surge absorber 3. Removing the propeller and the outdoor fan motor (1) Remove the cabinet. (Refer to 1.) (2) Remove the propeller nut. (3) Remove the propeller.
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OB387B-1.qxp 07.5.23 2:48 PM Page 29 OPERATING PROCEDURE PHOTOS Photo 6 4. Removing the compressor (1) (2) (3) (4) (5) Remove the cabinet. (Refer to 1.) Remove the relay panel. Remove the soundproof felt. Remove the terminal cover on the compressor. Disconnect lead wires from the glass terminal of the compressor. (6) Recover gas from the refrigerant circuit. NOTE : Recover gas from the pipes until the pressure gauge shows 0 kg/cm2 (0 MPa). (7) Disconnect the welded part of the discharge pipe.
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OB387B-1.qxp 13 07.5.23 2:48 PM Page 30 PARTS LIST (non-RoHS compliant) MUH-GA20VB MUH-GA25VB MUH-GA35VB 13-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND FUNCTIONAL PARTS 22 21 20 19 18 17 16 15 14 1 2 24 23 3 13 4 5 6 7 8 9 10 11 This figure shows MUH-GA20VB.
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OB387B-2.qxp 07.5.23 2:50 PM Page 31 PARTS LIST (non-RoHS compliant) MUH-GA20VB MUH-GA25VB MUH-GA35VB 13-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND FUNCTIONAL PARTS Part numbers that are circled are not shown in the illustration. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Part No.
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OB387B-2.qxp 14 07.5.23 2:50 PM Page 32 RoHS PARTS LIST (RoHS compliant) MUH-GA20VB MUH-GA25VB MUH-GA35VB 14-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND FUNCTIONAL PARTS 22 21 20 19 18 17 16 15 14 1 2 24 23 3 13 4 5 6 7 8 9 10 11 This figure shows MUH-GA20VB.
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OB387B-2.qxp 07.5.23 2:50 PM Page 33 RoHS PARTS LIST (RoHS compliant) MUH-GA20VB MUH-GA25VB MUH-GA35VB 14-1. OUTDOOR UNIT STRUCTURAL PARTS, ELECTRICAL PARTS AND FUNCTIONAL PARTS No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 RoHS Part numbers that are circled are not shown in the illustration. G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G Part No.
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OB387B-2.qxp 07.5.
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OB387B-2.qxp 07.5.23 2:50 PM Page 36 HEAD OFFICE: TOKYO BLDG.,2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN C Copyright 2005 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD Distributed in May 2007. No.OB387 REVISED EDITION-B 6 Distributed in May 2006. No.OB387 REVISED EDITION-A 6 Distributed in Feb. 2005. No.OB387 6 Made in Japan New publication, effective May 2007 Specifications subject to change without notice.