Miller Electric pmn - Manual (Page 27)

OM-228 305 Page 23
6-5. Troubleshooting Power Source
Connect unit to proper input
voltage (see Section 4-8).
Yes
No
Is input power
connected to
correct line
voltage?
Is Changeover
switch S2 in
the 115V or
230V position?
Place Changeover switch in
proper position for input
voltage (see Section 4-8).
No
Yes
Is the cooling
fan running?
Check Power switch S1 and
relay CR2 and thermistor R1
on PC2. Replace PC2 if R1
or CR2 are not functioning
correctly.
No
Yes
Is Power light
flashing?
Reset Power switch S1
and verify line power
voltage (see Section 4-1).
Check relay CR2,
thermistor R1 on PC2,
and Control board PC1.
No
No
Yes
Turn Output control
fully counterclockwise (see
Section 5-1). Check for
gas/air flow at torch. Check
Control board PC1,
pressure switch S3 (gauge),
air filter, valve AS1, and air
supply connection to unit
and torch.
No
Yes Is Pressure Status
light On or flashing?
Press torch trigger and
check if pilot arc ignites.
Check torch consumables.
*Check torch connections,
air filter, pressure switch S3,
valve AS1, air supply
connection to unit, torch,
and PC1.
Yes
No Does pilot arc
ignite?
Place torch near workpiece
and check if pilot arc “jumps”
or transfers to workpiece.
Check work clamp
connection. *Check Control
board PC1 and connections,
and torch and its connections.
Yes
No Does pilot arc
transfer to
workpiece?
Check all connections,
Check main transformer T1,
Check boost inductor L1
and buck inductor L2.
Return to beginning of chart.
*Servicing procedure to be
performed only by authorized
Service Station.
*
*
*
Is Cup Status
light On or
flashing? Check torch consumables.
Reset Power switch S1. Yes
Is Power switch
S1 in the On
position?
Place Power switch in the
On position. (see Section
5-1).
Is Temp Status
light On?
If unit is overheated, wait
while fan cools down unit
temperature.
Yes
No
No
No
Yes Does the breaker
trip when unit is set
on 115V?
Turn down output current.
(see Section 5-1).
Yes