Troubleshooting
Low Welding Amps
Low welding amps can be caused by three components
A defective Excitation Bridge located on the bottom right hand corner
B an open fine control (Optional). Resistance should be 6 ohms.
C Thermal trip in the windings. Disconnect the two AC wires off the bottom right
hand Excitation Bridge (white&orange) and make a resistance reading.
With the
seven-step selector switch in the lowest position and the range switch and in the high
position you should get about 2 ohms. Move the seven-step switch while observing the
ohmmeter all the way to its highest position. The resistance should increase slightly
with every step. You should end up with about 3 ohms. If you do not start off with 2
ohms and the circuit shows open move your ohm meter 1 lead to the center terminal on
the range switch, the other ohm meter lead onto the terminal RL1 on the seven position
switch. If you have a reading, there about 2ohms the transformer is ok. To test for the
terminal trip in a windings take a reading between the center post of the range switch
and the white wire you remove from the Excitation Bridge. You should get 0ohms.
Any other readings on the trip are defective. To check the fine control put one-ohm
meter lead on the seven-step switch terminal RL1, the other lead on the orange wire
you removed from the Excitation Bridge. You should be able by moving the fine
control up and down adjust the ohmmeter reading between 0 and 6 ohms. To check the
Excitation Bridge, remove all wires from it and measure forward and backward
going around clockwise. In any position and in any combination between terminals
you should get a high and low reading. If any of the readings come out the same, the
bridge is defective.
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