Valley FABRICATOR 251 Service Manual - page 5
TABLE OF CONTENTS (continued)
TABLE OF CONTENTS
SECTION 4:
OPERATION ........................................................................................... 4-1
4.01 Power Supply Controls, Indicators and Features ............................................ 4-1
4.02 Weld Mode Selector ....................................................................................... 4-6
4.03 400 Amp Air-Cooled MIG Gun ........................................................................ 4-8
4.04 Installing A New Wire Conduit ........................................................................ 4-9
4.05 MIG Gun Maintenance .................................................................................. 4-10
4.06 Basic Welding Technique .............................................................................. 4-10
4.07 Stitch Welding Operation .............................................................................. 4-12
4.08 Spot Welding Operation ............................................................................... 4-12
4.09 Gas Selection for Gas Metal Arc Welding ..................................................... 4-13
4.10 Welding Setting Selection Guide .................................................................. 4-14
SECTION 5:
MAINTENANCE ....................................................................................... 5-1
5.01 Routine Maintenance & Inspection ................................................................. 5-1
SECTION 6:
BASIC TROUBLESHOOTING ........................................................................ 6-1
6.01 Basic Troubleshooting .................................................................................... 6-1
6.02 Solving Problems Beyond the Welding Terminals .......................................... 6-2
6.03 Welding Problems .......................................................................................... 6-4
6.04 Power Supply Problems ................................................................................. 6-6
SECTION 7:
ADVANCED TROUBLESHOOTING .................................................................. 7-1
7.01 Preliminary Checks ......................................................................................... 7-1
7.02 Initial Setup Conditions .................................................................................. 7-2
7.03 Primary Power Test ........................................................................................ 7-2
7.04 Logic and Control Tests .................................................................................. 7-3
7.05 Spool Gun Control (J1) Test ........................................................................... 7-4
7.06 Output Voltage Test ........................................................................................ 7-5
7.07 Wire Feed & Weld Test .................................................................................. 7-6
7.08 Primary Power Problems ............................................................................... 7-6
7.09 Logic and Control Problems ........................................................................... 7-7
7.10 Spool Gun Control (J1) Problem .................................................................... 7-8
7.11 Output Voltage Problem ................................................................................. 7-8
7.12 Wire Feed and Weld Problems ....................................................................... 7-9
7.13 Terminal Block Voltage Test ............................................................................ 7-9
7.14 SW3 Coarse and SW4 Fine Rotary Switch Test ............................................ 7-10
7.15 MIG Timer PCB (PCB2) Test ......................................................................... 7-12
7.16 Rectifier Assembly Test ............................................................................... 7-13
7.17 Main Transformer Test ................................................................................. 7-14