Troubleshooting & repair, Thermal protection ac trigger circuit (cont.), V300-pro – Lincoln Electric INVERTEC V300-PRO SVM105-B User Manual
Page 75
V300-PRO
TROUBLESHOOTING & REPAIR
4. Locate the Auxiliary Transformer T1 and leads used
for test. See Figure F.21.
5. Turn main power ON.
6. Test Auxiliary Transformer voltage for 24 VAC
between leads 503 and 212D. See Figure F.21.
a. If 24 VAC is present, transformer is OK. Go to
step 7.
b. If 0 VAC is present, test input voltage to Auxiliary
Transformer.
c. If input voltage to Auxiliary Transfor-mer is cor-
rect, replace Auxiliary Transformer.
d. If input voltage to Auxiliary Transfor-mer is not
correct, check Line Switch S12 and connecting
leads.
7. Check that Output Terminal Switch S4 is in the ON
position (closed).
8. Test for 24 VAC between leads 223A and 210.
a. If 24 VAC is present, then AC Trigger Circuit is
functioning normally.
b. If 0 VAC is present, check Choke Thermostat
and Fan Thermostat.
F-45
F-45
THERMAL PROTECTION AC TRIGGER CIRCUIT (cont.)
FIGURE F.21 - THERMAL PROTECTION AC TRIGGER CIRCUIT
CONTROL
BOARD
POWER
BOARD
T1
11J4
EXTERNAL
TRIGGER
S4 OUTPUT
TERMINAL
SWITCH
FAN
THERMOSTAT
CHOKE
THERMOSTAT
PART OF 14 PIN
AMPHENOL
NORMALLY CLOSED
NOTE:
WHEN THERMOSTATS
TRIP, THE CIRCUIT
WILL BE OPENED
9J6
10J6
#210
4J2
#223A
#224
#503A
#503
#212B
#212A
#212C
#223B
#212D
24
VOLTS
AC
4D
C
2