Nelson ALPHA 850 - Page 56

9 Repairs Page 51
Stud welding unit operating manual Date: July 2021
ALPHA 850 07.2021 / EN Rev.: A
Fault: Gun function
Features:
• ALPHA 850 is switched on
• “System voltage" LED lights up
• Fan runs
• The “Fault” multi-function LED doesn’t go on
• Gun doesn’t work when start triggered
• no weld
No.
Possible
cause
What is to be
tested or how?
Test
result
Test result achieved?
yes no
1
Gun cable has no
connection
The “Coil” LED does or
doesn’t go on?
lights No. 9 No. 2
2
Gun cable has no
connection
Check control cable
connection
OK No. 3
Make the
connection
3
Control line defective
Control cable: Measure
Pin 1 against Pin 2
R ≈ 20 Ω No. 7 No. 4
4
Coil defective
Measure the coil
R ≈ 20 Ω No. 5 No. 6
5
Control line defective
Replace the control
cable
Replace gun
OK ready No. 12
6
Coil defective
Replace the coil
Replace gun
OK ready No. 12
7
PCB connection
defective
Check the connection
plug of PCB X1/X3
1)
*) OK No. 8
Make the
connection *)
8
Fuse defective
Check the equipment
fuse F2 and F3
2)
*)
OK ready No. 12
9
Start button defective
“Start weld cycle” LED
ON?/OFF? when
triggered?
OFF No. 10 No. 11
10
Start button defective
Replace the start button
Replace gun OK ready
No. 12
Start
detection
11
No lift set
Set lift
OK ready No. 12
12
Shut down ALPHA 850
Notify Tucker service!
Tasks indicated with *) must be done only by electro-technical personnel!
1)
The arrangement of the plug connections (X1, X3) on the internal control card can be found in the
illustration on page 54.
2)
The arrangement of the equipment fuses on the internal control card (F2, F3) can be found in
Chapter 6 “Equipment fuses” or in the illustration on page 54.