22
-Faulty potentiometer
- One of the two rectifier diodes
(Fig. 5 # 27) is not conducting.
Substitute the potentiometer
How to spot the faulty diode:
1)
Remove the cover ( Fig. 5 #
32) from the frame.
2)
Start the welder and let it
work for 5-6 minutes with the flame
off and the power control set at the
maximum value.
3)
Unplug the welder and
touch immediately the body of the
two rectifier diodes.
4)
The temperature of the
faulty diode is lower than that of the
other diode.
How to replace the faulty diode:
Spread silicone grease all over the
contacts surface of the new diode,
mount it and tighten the stop nut
underneath using dynamometric
wrench set from 0,25 to 0,32 Kgm.
5)
On starting the machine the
fuse blows out. (Fig.5 # 37)
-
Power circuit board is short
circuited
-
One of the rectifier diode is
short-circuited.
-
Short
–circuit inside the tank
(Fig. 5 # 50 ), due to accidental
introduction of a metal object.
-
Short-circuit of the tank
cover ( Fig. 5 # 46 ) with the tank,
due to over compression of the
cover “OR”
( Fig. 5 # 49 ).
Substitute the power circuit board
How to spot the short-circuited
diode:
1)
Disconnect the terminals of
the two diodes
( Fig. 5 # 27) from the copper flat
conductors
2)
Using an OHM meter ( at
OHM 1 ) measure the resistance
between the body and the diode,
nominal value of 600-2000 OHM.
The defective
diode, gives a very low value
even if you invert
the Ohm Meter
points.
3)
Replace the faulty diode .
