Troubleshooting Flowcharts For Idle Control Board/Module Pc1 - Miller Electric Legend AEAD-200LE Technical Manual

6-6. Troubleshooting Flowcharts For Idle Control Board/Module PC1

Engine does not go to power/idle rpm
with no weld load applied.
Connect meter (AC) between
terminal G and terminal E.
Start engine. Place Engine Control
switch S2 in Run/Idle position.
0 (zero) volts ac present?
YES
Connect meter (DC) between
terminal D (+) and E (–).
0 (zero) volts dc present?
YES
Connect meter (DC) between
terminal C (+) and terminal E (–).
0 (zero) volts dc
present after 12 to 18 seconds?
YES
Check throttle solenoid TS1
linkage.
Reinstall cover.
TM-428 Page 24
Check for internal
NO
load such as
shorted diode in
main rectifier SR1.
NO
Check connections
to Engine Control
switch S2.
NO
Replace idle
board/module
PC1
Engine does not go to weld rpm with
load applied.
Connect meter (DC) between
terminal B (+) and terminal E (–).
Start engine. Place Engine Control
switch S2 in Run/Idle position; Idle
Lock switch S1 in Unlock position.
+12 volts dc present?
YES
Connect meter (AC) between
terminal G and terminal E.
Start engine. Place Engine
Control switch in Run/Idle position.
Connect a 100 watt light bulb to
100 Hz ac receptacle.
Minimum of 1 volt ac present?
YES
Connect meter (DC) between
terminal C (+) and terminal E (–).
+12 volts dc present?
YES
Check circuit breaker CB4, throttle
solenoid TS1 connections and
linkage, and control relay CR2.
Disconnect 100 watt light bulb
and meter leads.
Reinstall cover.
Check connections
NO to Engine Control
switch S2 and
ground connection
(lead 33).
NO
Check connections
to current
transformer CT1.
NO Replace idle
board/module
PC1
Miller Legend