SECTION 3—OPERATING PROCEDURES & TROUBLESHOOTING
Detect-A-Finger
®
Drop Probe Device-Welder
Rockford Systems, LLC
Call 1-800-922-7533
17
Operating Procedure
1. Apply power. If the power does not come on, check that the main disconnect switch is on, fuse is connected, and check
for proper wiring.
2. Measure the incoming voltage at terminals 1 and 2. It should be 115 V AC ± 15%. Shut off power for the next step.
3. The sensing probe should be in position over the workpiece and formed to protect the required area. Move the drop rod
manually to the point where the limit switch (in the control box) is actuated and locate the sensing probe to be no more
than 1⁄4 inch above the workpiece. Check this adjustment periodically and before every setup.
4. Reapply power—the welder should be ready to cycle. Depress the foot switch. The Detect-A-Finger® rotary solenoid
should energize, permitting the drop rod to drop until the limit switch is actuated. The limit switch now energizes the
control relay and the relay contacts close, energizing the welder controller or operating device (solenoid). The welder
electrodes should close thus permitting the parts to be welded.
Troubleshooting
Voltage Measurement Troubleshooting
SYMPTOM
TEST POINTS
READING
PROBLEM
No Power
Rotary Solenoid
Will Not Energize
“Power On”
Rotary Solenoid
Energizes, Welder
Will Not Cycle
“Power On”
Rotary Solenoid
Energizes, Welder
1st Stage (Squeeze)
Operates, 2nd Stage
(Weld) Will Not Function
Terminal 1-2
Terminal 2 to wire common
with fuse and light to door
Terminal 3-W
Terminal 4-W with
foot switch depressed
Terminal BR-W with
foot switch depressed and
sensing probe held up
Terminal R-W
with foot switch
depressed
Disconnect FS1 and 2 from Terminals 5 and 6.
Terminals 5-6
(Single stage)
Disconnect FS3 and 4 from Terminals 8 and 9.
Terminals 7-9
and 7-8 (2nd stage)
0
60 V AC
230 V AC
115 V AC
0
115 VAC
0
24 V AC
0
24 V AC
0
24 V AC
0
24 VAC
Carefully check continuity with test light or ohmmeter when the foot switch is
depressed. The relay contact (Terminals 7-9) should close. The foot switch
contact (Terminals 7-8) should close. If not, replace the defective component.
If these contacts (Terminals 8-9) close properly, the problem is with the welder
controller. Reconnect FS3 and 4.
No primary power.
Transformer wired for 460 V AC, 230 applied.
Transformer wired for 230 V AC, 460 applied.
Proper voltage applied, continue.
Fuse blown, replace.
Defective lamp, replace.
Transformer defective, replace.
Proper voltage, continue.
Foot switch defective or improperly connected,
locate problem and correct.
Proper voltage, continue.
Relay contact (N.C.) defective, replace relay.
Proper voltage—bridge rectifier or rotary solenoid
defective. See resistance measurement section.
Limit switch not being actuated or limit switch
defective. Replace limit switch.
Proper voltage—relay coil open.
“Power On” Indicator
Will Not Light
“Power On”
Indicator is Lit,
Rotary Solenoid
Will Not Energize
Carefully check continuity with test light or ohmmeter when the foot switch is
depressed. The relay contact should close. If not, replace relay. If the relay
contact closes properly, the problem is with the welder operating device or
wiring is defective. Check continuity with an ohmmeter. Reconnect FS1 and 2.
