Lincoln Electric IDEALARC R3R-300 Service Manual page 35

Section F-1
- TROUBLESHOOTING & REPAIR SECTION -
Troubleshooting & Repair Section ......................................................................................Section F
How to Use Troubleshooting Guide............................................................................................F-2
PC Board Troubleshooting Procedures ......................................................................................F-3
Troubleshooting Guide.......................................................................................................F-4 - F-9
Test Procedures
Input Contactor Test (Equipped with AC Coil) ...................................................................F-10
Input Contactor Test (R3R 300 Equipped with DC Coil)....................................................F-13
Control Transformer (T2) Voltage Test ................................................................................F-16
Main Transformer (T1) Voltage Test ....................................................................................F-19
Static SCR/Diode Rectifier Bridge Test..............................................................................F-24
Active SCR Test..................................................................................................................F-28
Pocket Amptrol Circuit Test................................................................................................F-31
Oscilloscope Waveforms ..........................................................................................................F-35
Normal Open Circuit Voltage Waveform-Maximum Output, No Load...............................F-35
Typical Output Voltage Waveform-Machine Loaded..........................................................F-36
Typical SCR Gate Voltage Waveform-Maximum Output, No Load....................................F-37
Abnormal Open Circuit Voltage Waveform-One Output SCR Not Functioning.................F-38
Replacement Procedures .........................................................................................................F-39
Input Contactor (CR1) Cleaning/Replacement...................................................................F-39
Fan Motor and Blade Removal and Replacement.............................................................F-41
SCR/Diode Rectifier Assembly Removal and Replacement..............................................F-43
SCR Removal and Replacement........................................................................................F-46
Mounting of Stud Type Diodes to Aluminum Heat Sinks...................................................F-52
Main Transformer Removal and Replacement ...................................................................F-54
Retest After Repair....................................................................................................................F-61
TABLE OF CONTENTS
NOTE: This manual is based primarily on the model R3R
500. Where tests or other procedures differ sig-
nificantly for models R3R 300 and R3R 400, those
differences are noted.
IDEALARC R3R
Section F-1