Lincoln Electric LN-25 PRO DUAL POWER Service Manual page 46

E-4
ELECTRODE
INPUT
INPUT
21
14 PIN AMPHENOL
REMOTE
VOLTAGE
PRESET BOARD (DISPLAY)
The preset board (display) is responsible for displaying
the voltage and current as well as giving a path for the
input voltage to get to the control board. The preset
(display) board is powered off the SPI lines once the
control board has been powered up. When using the
control cable for input power, the preset (display) board
will allow for the remote voltage control via the voltage
control potentiometer.
THEORY OF OPERATION
FIGURE E.4 - PRESET BOARD (DISPLAY)
CURRENT TRANSDUCER
CONTACTOR
SOLENOID POLARITY
SP1
CONTROL BOARD
POWER
SUPPLY
COLD CC
FEED CV
RUN IN
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion
LN-25™ PRO DUAL POWER
67
TIMER OPTION
MOTOR
MOTOR
OVERLOAD
ARMATURE
TACH FEEDBACK
GUN TRIGGER
TRIGGER
GAS
INTERLOCK
PURGE
E-4
FEEDPLATE
TACH
GUN
WIRE
SPEED