A. Preliminary Checks
1.
Check that jumper plug PLGl is secure in recep-
tacle RC1 on Motor Control Board PCl.
2.
Check that plug PLG2 is secure in receptacle
RC2 on Motor Control Board PCl.
3.
Check that plug PLG3 is secure
receptacle
in
RC3 on Motor Control Board PCl.
4.
Check that plug PLG4 is secure in receptacle
RC3 on Motor Control Board PCi.
B. Power Supply Circuit
Input power of 24 volts ac should be present between
pins A and B of receptacle RC4. If 24 volts ac are not
present, check POWER switch 51 and circuit breaker
CBl for proper operation with an ohmmeter.
An output voltage of +24 volts dc should be present at
pin A of receptacle RC2 with respect to circuit common.
If +24 volts dc are not present at pin A, replace Motor
Control Board PCl.
An output voltage of +6.5 volts dc should be present at
pin C of receptacle RC2 with respect to circuit common
with gun trigger pressed. If +6.5 volts dc are not present
at pin C, replace Motor Control Board PCi.
C. Trigger Circuit
When the gun trigger is pressed, +19 volts dc should be
present at pin B of receptacle RC2 with respect to circuit
common otherwise the voltage at pin B should be 0 volts
dc when the gun trigger is not pressed. The trigger signal
is then supplied to pin A of receptacle RCl as a motor
start/stop control signal and also supplied to pin B of re-
ceptacle RCl to control gas valve GS1 and contactor
control relay CR1 on PCi.
D. Wire Feed Speed Circuit
The 0 to +6.5 volts dc wire feed speed command input
signal should be present at pin D of receptacle RC2. The
wire feed speed command signal is compared to the
current and voltage feedback from Motor Ml thereby
providing the proper voltage output of 0 to +24 volts dc
to wire drive motor Ml through pins D (positive) and C
(negative) of receptacle RC4. If 0 to +24 volts dc is not
present between pins C and D of RC4, replace Motor
Control Board PCi.
TM-i 57i Page 17