TROUBLESHOOTING & REPAIR
F-47 F-47
SQUARE WAVE TIG 275
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SCR BRIDGE ASSEMBLY REMOVAL AND REPLACEMENT (continued)
FIGURE F.13 – SCR BRIDGE CONNECTIONS
For Steps 7-13, see Figure F.13.
7. Using the 7/16” wrench, label and remove the
“POS” lead from the left side heat sink assem-
bly. It is not necessary to remove the #218
lead.
8. Using the 7/16” wrench, label and remove the
“NEG” lead from the D1 diode pigtail.
NOTE: It will be necessary to remove the
sleeve insulation to gain access to the con-
nection.
9. Remove plug J1 from the control board. Also
remove the plug and lead harness from the
internal divider panel.
10. With the 1/2” wrench, remove the X2 trans-
former secondary lead from the right side
heat sink assembly. It is not necessary to
remove the jumper lead or the #216 lead.
11. With the 7/16” wrench, remove the shunt and
one #220 lead from the right side negative
heat sink assembly. It is not necessary to
remove the other #220 lead.
12. Using the 1/2” wrench, remove the “B” lead
from the AC left side heat sink. It is not nec-
essary to remove the copper jumper or the
#217 lead.
13. Using the 3/8” wrench, remove the four
mounting screws holding the SCR Bridge
Assembly to the transformer iron assembly.
14. Carefully remove the SCR Bridge assembly
from the machine.
