8
Fault
Resolution
Fan running, welding cur-
rent not stable or out of
control, current varying
between high and low
amperage.
A. 1K potentiometer is faulty, replace
B. Output terminal is faulty or poorly connected.
Fan is running and Fault
indicator is lit but there
is no welding current.
A. Check if components have poor contact.
B. Check connection of output terminal and check for broken circuit or poor
connection.
C. Check voltage between PCB and MOS boards(VH-07)
(approx 380V DC)
D. If the green indicator light is not lit on MOS board, return to the distributor or
agent.
E. If the Control circuit faulty, please contact the distributor or agent.
Fan running and Fault
indicator is lit but no
output current.
A. Over current protection circuit enabled. Turn off the machine and wait 5-10
minutes. Once the Fault indicator is not lit, Inspect machine internally.
B. Overheat protection circuit is enabled. Wait 2-3 minutes.
C. Inverter circuit in fault.
1.) If the fault indicator is still lit, MOS damaged, check and replace.
2.) If Fault indicator not lit;
i. Middle board transformer potentially faulty. Measure primary inductance
volume and Q volume of main transformer by inductance bridge.
ii. Primary volume is parallel circuit, L=1.2-2.0Mh. Q>40 if inductance and Q
volume is low, Replace it.
iii. Secondary rectifier tube of the transformer is faulty. Check for faults and
replace the rectifier tube.
D. Feedback circuit is faulty.