4. troubleshooting – Miller Electric 812 User Manual

Page 33

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A complete Parts List is available at www.MillerWelds.com

OM-278 Page 25

6-4. Troubleshooting

Trouble

Remedy

No weld output; unit completely

inoperative; pilot light PL1 off.

Place line disconnect device in On position (see Section 4-18).

Check for open line fuse(s), and replace if open (see Section 4-18).
Check for proper input power connections (see Section 4-18).
Check for proper jumper link position (see Section 4-17).
Check fuse F1, and replace if necessary (see Section 6-2).

No weld output; power switch pilot light

on.

Unit overheated. Allow unit to cool with fan On (see Section 4-2).

If using remote control, place Output (Contactor) switch in Remote 14 position, and connect remote

control (see Sections 4-14 and 4-15). If remote is not being used, place switch in On position (see

Section 5-1).
Check, repair, or replace remote control.

No weld output; power switch pilot light

fa ff

Check for proper input power connections (see Section 4-18).

p

p

p

g

on; fan off.

Check for open line fuse(s), and replace if open, or reset circuit breaker (see Section 4-18).
Turn power switch off then back on. If no output condition remains, have Factory Authorized Service

agent check SCR’s.

Limited weld output and low

open-circuit voltage.

Check position of Remote Amperage/Voltage Control switch (see Section 5-1).

Check for open line fuse(s), and replace if open (see Section 4-18).
Check for proper input power connections (see Section 4-18).
Check for proper jumper link position (see Section 4-17).
Clean and tighten all weld output connections.

Unit provides only maximum or

minimum weld output.

Have Factory Authorized Service Agent check control board PC1 and hall device HD1.

Check position of Remote Amperage/Voltage Control switch (see Section 5-1).

Not able to obtain minimum output in

CC mode.

Use high inductance weld output terminal when in CC mode to obtain minimum output (see Section

4-9).

Erratic or improper weld output.

Use proper size and type of weld cable (see Section 4-9).
Clean and tighten all weld connections.
Check wire feeder installation according to Owner’s Manual.
Check position of Process selector switch (see Section 5-1).
Have Factory Authorized Service Agent check control board PC1 and hall device HD1.

No 115 volts ac output at duplex recep-

tacle, or Remote 14 receptacle.

Reset supplementary protector CB1 (see Section 4-7).

No 24 volts ac output at Remote 14 re-

ceptacle.

Reset supplementary protector CB2 (see Section 4-7).

Fan not operating. Note: fan only runs

when cooling is necessary.

Check for and remove anything blocking fan movement.

Have Factory Authorized Service Agent check fan motor.

Wandering arc; poor control of arc

direction.

Reduce gas flow rate.

Select proper size tungsten.
Properly prepare tungsten.

Tungsten electrode oxidizing and not

remaining bright after conclusion of

weld.

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.

Digital meter not working properly.

Have Factory Authorized Service Agent check control board PC1 and connections, and replace if

necessary.

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