LG Electronics 553cc Welding System User Manual


 
18
CONDITION ACTION
Unit Inoperative A. No input power. Check main line (user's) switch fuses -- replace if needed.
B. Poor or improper input (terminal board) connections.
C. Defective on/off switch on front panel -- replace.
D. Main transformer overheating. Also check for proper cooling, proper primary hookup,
or shorted turn on secondary.
E. Fan motor not operating -- check motor and leads.
F. Gound fault indicator "ON". - Check for cause and correct. Turn power switch "OFF"
then "ON" to reset.
G Loss of primary phase. Check that LED on control PCB is lit. If not, find & replace
defective fuse.
No Output - Fan A. Poor or improper electrical input -- check input connections on TB.
Running B. Poor connections at output terminals/work station -- check, tighten or replace.
C. Main transformer overheating -- thermal switches tripped due to restricted cooling air.
Temperature light on front panel will be lit. Let unit cool down,
D. Solid-state breaker tripped due to current overload.
E. PC board defective or loose PC board connector(s) -- if loose, reinsert; if defective,
replace.
Limited Output or Low A. Input voltage jumper links on terminal board improperly set -- check for proper voltage.
Open-Circuit Voltage Poor output connections. Take apart, clean, and reassemble.
B. Unit may be single phasing -- check incoming power for three phases.
C. Panel-Remote switch in Remote position and remote voltage pot disabled.
Erratic Weld Current A. Welding cable size too small -- use correct cables.
B. Loose welding cable connection (will usually get hot) -- tighten all connections.
C. Improper wire feeder setup.
D. Defective SCR in bridge rectifier.
E. PC board defective -- replace.
High Output, No A. PC board defective or loose -- reset and/or replace board.
Voltage Control
No 115 Volt ac Output A. Circuit breaker tripped. Check 42V CB1 and 115V CB2 -- Reset.
Line Fuse Blows When A. Shorted SCR in Main Bridge -- replace.
Power Source is First
Turned On
SECTION 5 TROUBLESHOOTING