Pro-Weld ARC 1850, Operation Manual

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ARC 1 8 5 0
PRO WEL D
10.0 TROUBLE SHOOTING
Whenever possible, have a qualified electrician do the maintenance and trouble shooting work. Turn the input power off us-
ing the disconnect switch at the fuse box before working inside the machine.
Trouble Possible Cause What To Do
Unit trips off without 1. Defective main SCR. 1. Check for defective SCR and
welding. replace.
2. Defective sustaining arc SCR. 2. check and replace.
3. Defective 600-0012 P.C. board. 3. Replace.
4. Defective 600-0010 P.C. board. 4. Replace.
5. Shorted control cables. 5. Repair.
Low output. 1. Input fuse blown. Unit is single 1. Replace fuse, repair input line.
phase. Check for reason for fault.2.
2. Incorrect jumper link connection 2. Check jumper links on primary
on primary board. board for proper voltage.
3. Defective 600-0012 P.C. board. 3. Replace.
4. Defective 600-0010 P.C. board. 4. Replace.
5. Defective current potentiometer. 5. Replace.
Maximum output but 1. Defective 600-0012 P.C. board. 1. Replace.
no control. 2. Open lead going to shunt 2. Repair broken leads on
(shielded cable). connection.
3. Defective current potentiometer. 3. Replace.
Gun does not lift. 1. Blown 5 amp fuse. 1. Check and replace fuse.
2. Defective 600-0010 P.C. board. 2. Replace.
3. Defective control cable or 3. Repair short in cable, replace
gun coil. gun coil.
4. Defective 600-0012 P.C. board. 4. Replace.
5. Defective 600-0011 P.C. board. 5. Replace.
6. Unit Overheated. 6. Allow unit to cool/ then reduce
weld rate to prevent reoccurrence.
7. Defective thermal switch. 7. Check and replace.
Gun lifts but does not 1. Blown 25 amp sustaining arc fuse. 1. Check and replace fuse.
weld. 2. Defective sustaining arc SCR(s). 2. Replace bad part(s).
3. Defective 600-0010 P.C. board. 3. Replace.
4. Defective 600-0012 P.C. board 4. Replace.
5. Defective choke coil. 5. Check and Replace.
6. Open weld cable or bad weld 6. Check and Repair.
ground connection.
Gun lifts but does not plunge 1. Defective 600-0010 P.C. board. 1. Replace.
2. Defective time potentiometer. 2. Replace.
Display inoperative 1. Defective 600-0011 P.C. board. 1. Replace.
2. Defective display. 2. Replace..
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