Replacement Of The Slide-In Electronic Module; Troubleshooting Guide - GT WTU 457 Mode D'emploi

REPLACEMENT OF THE SLIDE-IN ELECTRONIC MODULE

Attention! This should only be carried out by FRONIUS service
personnel or by other suitably trained and skilled technicians.
Procedure
- Switch off machine
- Pull out mains plug
- Unscrew and remove the toggle from the mains switch
- Unscrew the six screws on the front control panel and swing it outwards
- Unlatch the plug-in connection
- Pull out the flat plug connected to the yellow / green earth lead
- Replace the module
- Assemble the unit in the reverse order

TROUBLESHOOTING GUIDE

Attention! Machine may only be opened by trained personnel !
FAULT
No welding current
Mains switch ON
Control lamp ON
Welding current cannot be regulated
Mains fuse blows as soon as machine is
switched on
Machine constantly delivers maximum
current
Poor welding caracteristics
(high degree of spattering)
but welding current is identical to value set on
scale
Fig. 19
CAUSE
machine overloaded
thermostat has switched off
no connection with workpiece
defective thermal protector
faulty electronic unit
changeover switch "external - internal" in
incorrect position
break in remote control cable
remote control unit faulty
faulty electronic unit
defective power thyristors, power diodes or trans-
former
shunt connections loose (twisted grey / black
lead)
incorrect polarity of welding electrode
selctor switch is incorrect position
incorrect connection of mains plug
phase missing in mains
defective diode or thyristor
faulty electronic unit
13
REMEDY
check fan
let machine cool down (remember duty cycle!)
check earth connection
replace
replace
shift to correct position
replace
replace
replace
check thyristors, diodes and transformer, and
replace if necessary
tighten connections (ensure correct polarity)
change polarity (observe manufacturer's in-
structions)
shift switch in correct position
check the connection of mains plug
check mains fuse, mains switch and mains
terminal board if using special voltages
check and replace if necessary
replace