F-15-621 8/2000
KNOB SKIRT, P/N 951502 (4)
250K 2W POTENTIOMETER,
P/N 599670 (4)
KNOB SKIRT
P/N -951502
TOGGLE SWITCH DPDT
P/N 950458 (1)
SPOT/BURNBACK PC
BOARD P/N 31471 (1)
Fig. 4 -Burnback Control Front View
Fig. 5 -Burnback Control Side View
OPERATION
Description of Control Functions (see Fig. 4):
1. Preflow/Postflow - The PREFLOW control sets
the time of the preflow shielding gas before the wire
starts feeding (0-1.5 sec.). The POSTFLOW control
sets the time the shielding gas remains “ON” after
the arc is turned “OFF” (0-7.5 sec.).
2. Spot Weld Time - This knob sets the spot weld
time from 0 to 5 seconds and is controlled by a
current sensor switch. The timer does not start until
current is detected to insure consistent results.
3. Burnback Timer - The burnback control knob
adjusts the time between the wire feed brake signal
and the welding contactor “off” signal. This
determines how far the wire will burnback towards
the contact tip after welding is completed. If the
wire is sticking in the weld pool, turn the knob
clockwise a small amount and retest. Continue this
procedure until the wire cleans the top of the weld
pool or burns back the desired amount.
4. Spot Weld Switch Position - With the toggle
switch in the SPOT (left) position the SPOT timer
is turned “ON” and the spot weld time is controlled
by the SPOT WELD TIMER knob.
5. Continuous Position - With the toggle switch in
the CONTINUOUS (center) position the welding
continues as long as the Mig gun trigger is
depressed.
6. Trigger Lock Position, the welding process begins
when the gun trigger is depressed. Once the
welding process has started, the gun trigger may
be released without affecting the welding process.
To stop the welding operation, the gun trigger must
be depressed a second time. This allows a
continuous weld without having to continuously
hold the gun trigger.