Troubleshooting - Miller Electric Shopmaster 300 AC/DC Owner's Manual

4-3. Troubleshooting

Trouble
No weld output; unit completely
inoperative.
No weld output; fan on.
Unit provides only maximum or
minimum weld output.
Weld output always above or always
below set value.
Erratic or improper weld output.
Fan not working.
No control of weld output.
No 115 volts ac output from duplex
receptacle or Remote 14 receptacle.
No 24 volts ac output at Remote 14 re-
ceptacle
Wandering arc – poor control of
direction of arc.
Tungsten electrode oxidizing and not
remaining bright after conclusion of
weld.
Place line disconnect switch in On position (see Section 2-10).
Check and replace line fuse(s), if necessary (see Section 2-10).
Check for proper input power connections (see Section 2-10).
Check for proper jumper link position (see Section 2-10).
If using remote control, place Output (Contactor) switch in Remote 14 position, and make sure remote
control is connected to Remote 14 receptacle. If remote is not being used, place Output (Contactor)
switch in On position.
Check, repair, or replace remote control.
Unit overheated. Allow unit to cool with fan On (see Section 2-3).
Have Factory Authorized Service Agent check control board PC1.
Have Factory Authorized Service Agent check control board PC1 and hall device HD1.
Have Factory Authorized Service Agent check control board PC1 and hall device HD1.
Use proper size and type of weld cable (see Section 2-6).
Clean and tighten all weld connections.
Check position of Output Selector switch (see Section Figure 3-1).
Have Factory Authorized Service Agent check control board PC1 and hall device HD1.
Check for anything blocking fan.
Have Factory Authorized Service Agent check fan motor.
If using remote control, place Amperage/Voltage control switch in Remote 14 position, and make sure
remote control is connected to Remote 14 receptacle. If remote is not being used, place switch in
Panel position.
Have Factory Authorized Service Agent check control board PC1.
Reset circuit breaker CB1 (see Section 4-2).
Reset circuit breaker CB2 (see Section 4-2).
Reduce gas flow rate.
Select proper size tungsten.
Properly prepare tungsten.
Shield weld zone from drafts.
Increase postflow time.
Check and tighten all gas fittings.
Properly prepare tungsten.
Check for water in torch, and repair torch if necessary. See torch Owner's Manual.
Remedy
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