Troubleshooting & repair, Leads x2 and x3 negative capacitor bank buss bar – Lincoln Electric WIRE-MATIC 255 SVM 119-A Manuel d'utilisation
Page 68
ACTIVE SCR RECTIFIER ASSEMBLY TEST (CONTINUED)
TEST PROCEDURE
1.
Disconnect main AC input power to
the machine.
2.
Disconnect Molex Plugs J3 and J6
from the G2803 Control Board.
See Figure F.5.
FIGURE F.5 - Control Board Molex
Plug Locations for G2803 PC Control
Board.
3.
Verify that the capacitors have com-
pletely discharged with an Analog
Volt-Ohm meter.
4.
Disconnect leads X2 and X3 from
the negative capacitor bank using a
1/2" open end wrench.
See Figure F. 6.
FIGURE F.6 - Location of Leads X2
and X3.
5.
Separate leads X2 and X3 from the
negative capacitor bank buss bar.
Be sure there is no electrical con-
tact. See Figure F.6.
NOTE: DO NOT DISASSEMBLE THE
SCR RECTIFIER HEAT SINK ASSEM-
BLY.
6.
Construct the circuit shown in Figure
F.7. One 6-volt lantern battery can
be used. R1 and R2 resistor values
are ±10%. Set voltmeter scale low,
at approximately 0-5 volts or 5-10
volts.
a.
Test the voltage level of the bat-
tery. Short leads (A) and (C).
Close switch SW-1. Battery
voltage should be 4.5 volts or
higher. If lower, replace the bat-
tery.
J2
J7
J4
J10
J6
J9
J3
J5
J1
G2803
WM-255 CONTROL
LEADS
X2 AND X3
NEGATIVE
CAPACITOR
BANK
BUSS BAR
F-17
TROUBLESHOOTING & REPAIR
F-17
WIRE-MATIC 255