ESAB LAW 400, Service Manual

Page: 31 / 66

-- 31 --
claw0de1
TEST ROUTINE
The test routine can be used if either the power unit or the wire feed unit has a digital
instrument. It must
not
be used when the gate connections are connected to the circuit board.
Activate the test routine by linking contacts J1 and J4 before energising the machine.
claw0e20
The test device
Do the following to activate the test routine.
S
Turn off the machine.
S
Disconnect connection XS14, carrying the gate pulses, from the circuit board.
S
If the machine is an LAW 500/510, disconnect connection XS9, machine type.
See the diagram below.
Connect the test device plug J to contacts J1 -- J4 on the circuit board.
claw0e09
Machine type / test input
S
Close switch S1 on the test device.
S
Start the machine.
The first test is of the display itself. All segments of the display should be visible and then
extinguished for one second.
If you close switch S2, between J3 and J4, the display will be extinguished.
Open S2 again.
Alternately open and close switch S1 to step through the test routine.
Change over S1 (i.e. from closed to open). The top line of the display now shows LL.1.
Each time that the switch changed, the count will increment by one. The explanations of the
various tests are as follows :
Test no.
LL.1 -- LL.7
These tests are not relevant here.
LL.8 Voltage setting.
Turn the potentiometer on the wire feed unit to adjust the voltage setting
between its upper and lower limits. The display must show 0 -- 255.