Lincoln Electric IM642 IDEALARC DC-600 - Manual (Page 41)

E-13 TROUBLESHOOTING E-13
IDEALARC® DC-600
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your
Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
CAUTION
CHECKING POWER ON/OFF SWITCH (S1)
1. Turn off the machine input power ("
o
"position).
SW1 has 115 volts across it when the input power
is connected.
2. Isolate the switch to be tested by removing all co-
nnecting leads.
3. Check to make sure the switch is making open and
closed connections with a V.O.M. meter. Put ohm
meter on X1 scale. The meter should read zero
resistance with switch "
I " and infinite with switch
"
o
"
4. Put the ohmmeter on X1K scale and measure the
resistance between the terminal and the case of the
machine (touch a self-tapping screw). Reading
should be infinite.
5. If either step (3) or step (4) fails, replace the switch.
CHECKING OUTPUT CONTROL RHEO-
STAT ON MACHINE (R1)
1. Turn machine off ("
o
" position).
2. Remove the screws from the hinged control panel
and open the panel.
3. Turn the LOCAL/REMOTE CONTROL switch to
"REMOTE".
4. With an ohmmeter on X1K, connect it to lead 236
and 237 on R1.
5. Exercise caution to avoid damaging rheostat tabs.
6. Rotate the OUTPUT voltage control rheostat. The
resistance reading should be from around zero to
10K ohms. Check the resistance reading between
the two outer tabs on the rheostat (leads 236 and
75). The reading must be 10K "10% ohms. No
reading will indicate an open rheostat and a low
reading will indicate a shorted or partially shorted
rheostat; in either case, replace.
CONNECTING REMOTE OUTPUT
CONTROL RHEOSTAT TO THE MACHINE
Extreme caution must be observed when installing or
extending the wiring of a remote control. Improper
connection of this unit can lead to loss of control
and/or poor welding. Only the green lead can and
should be grounded to the machine case. When
extending the standard remote control, make sure the
leads are the same and the splice is waterproof. Be
very careful not to ground the cable when in use and
don't let the lugs touch against the case.
CHECKING REMOTE OUTPUT CONTROL
RHEOSTAT
Disconnect the remote output control and connect an
ohmmeter across 75 and 76 and rotate the rheostat in
the remote control. The resistance reading should go
from zero to 10K ohms. Repeat with ohmmeter across
77 and 76 with same results. Connect ohmmeter
across 75 and 77. The reading should be 10K "10%
ohms. A lower reading will indicate a shorted or par-
tially shorted rheostat. A very high reading will indicate
an open rheostat. In either of the last two cases,
replace rheostat. Check cable for any physical dam-
age.