Lincoln Electric CV-300 Output Voltage, Fault Protection Operation, Checking Snubber Circuit

E-8 TROUBLESHOOTING E-8

OUTPUT VOLTAGE

The open circuit voltage of the machine should be 10 to 43 volts. If any other condition exists, refer to the Troubleshooting Guide.

FAULT PROTECTION OPERATION

The overload protection circuit on the PC Board will cause the CV-300 meter to display "E60". This pro- tection circuit will reset itself automatically. The short circuit protection circuit will cause the meter to display "E00". The CV-300 power switch must be turned "OFF" and then "ON" to return the machine to normal output.

CHECKING SNUBBER CIRCUIT

In case of an SCR malfunction or failure, the snubber assembly should be checked. Disconnect the input power to the CV-300 at the fuse box and remove the right side of the machine.

1.Visually inspect the snubber PC Board assembly (located below the Control PC board on the case front for overheated components or damaged compo- nents).

OPTIONAL K857 REMOTE CONTROL

CHECK

Disconnect the remote output control and connect an ohm- meter between pins C and B and rotate the rheostat in the remote control. The resistance reading should go from zero to 10K ohms. Repeat with ohmmeter across A and B with the same results. Connect ohmmeter across A and C. The reading should be 10K ohms. A lower reading will indicate a shorted or partially shorted rheostat. A very high reading will indicate an open rheostat. In either of the last two cases, replace the rheostat.

CAUTION

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.

CV-300