Lincoln Electric SQUARE WAVE TIG 355 Service Manual page 94

F-42
PROTECTION PC BOARD TEST (continued)
FIGURE F.11 – PROTECTION PC BOARD LOCATION AND MOUNTING DETAILS
PROCEDURE
1. Remove input power to the machine.
2. With the 5/16" nutdriver, remove the screws and
carefully lower the front control panel.
3. Remove plugs J22 and J23 from the protection
PC board. See Figure F.11 for location.
4. With the phillips screwdriver, remove the three
screws mounting the protection PC board to the
front panel. Note washer placement.
5. Carefully remove the protection PC board.
6. Test for the resistances between the check
points listed on the Protection PC Board
Resistance Test Points Chart.
• If any of the resistances are out of specifica-
tion, replace the protection PC board.
TROUBLESHOOTING AND REPAIR
SQUARE WAVE TIG 355
7. After the tests are complete and the problem
repaired, install and connect the protection PC
board.
• Carefully mount the protection PC board to
the front panel. Take note of the washer
placement; the washers must be replaced
correctly to be sure that the protection PC
board is grounded properly. See Figure F.11.
• Connect plugs J22 and J23.
8. Install the front control panel, using the 5/16"
nutdriver.
F-42