Lincoln Electric IDEALARC SP-250 Service Manual page 70

F-23
ACTIVE SCR RECTIFIER ASSEMBLY TEST
TEST PROCEDURE
1. Disconnect main AC input power to
the machine.
2. Disconnect Molex Plugs J3 and J6
from the G2252 Control Board or
remove Plug J3 from G1992 Control
Board (Code 9402 only)
See Figures F.5A and F.5B.
J2
J7
J4
J5
J6
FIGURE F.5A - Control Board Molex
Plug Locations for G2252 PC Control
Board.
J2
J7
J4
J5
J3
FIGURE F.5B - Control Board Molex
Plug Locations for G1992 PC Control
Board (Code 9402 only.)
TROUBLESHOOTING & REPAIR
3. Test with an Analog Volt-Ohm meter
4. Disconnect leads X2 and X3 from
SP-250 CONTROL
G2252
J8
J3
J9
FIGURE F.6 - Location of Leads X2
and X3.
5. Separate leads X2 and X3 from the
SP-250 CONTROL
G1992
NOTE: DO NOT DISASSEMBLE THE
SCR RECTIFIER HEAT SINK ASSEM-
BLY.
J8
6. Construct the circuit shown in Figure
J9
J6
IDEALARC SP-250
that capacitors have completely dis-
charged.
the negative capacitor bank using a
fi" open end wrench.
See Figure F. 6.
LEADS
X2 AND X3
NEGATIVE
CAPACITOR
BANK
BUSS BAR
negative capacitor bank buss bar.
Be sure there is no electrical con-
tact. See Figure F6.
F.8. 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.
voltage should be 4.5 volts or
higher. If lower, replace the bat-
tery.
F-23
Battery