Torch & Leads Troubleshooting; Repairs & Replacement Procedures; General Information - Firepower FP-18 Service Manual

4. Loose shield cup.
a. Tighten shield cup.
5. One or more gas distributor holes blocked.
a. Replace Gas Distributor.
6. Excessive parts wear.
a. Inspect torch consumables and replace as nec-
essary.
7. Damaged torch insulator
a. Check insulator between anode and cathode for
charring per subsection 3.6, Torch and Leads
Troubleshooting.
3.6 Torch & Leads
Troubleshooting
Disconnect primary power to the system before dis-
assembling the torch, leads, or power supply.
DO NOT touch any internal torch parts while the
AC indicator light on the front panel of the power
supply is on.
Torch parts may get quite hot during normal op-
eration. Always wear light cutting gloves when
changing torch parts just after operating the FIRE-
POWER system.
A. Checking the Center Insulator
The Center Insulator separates the negative and positive
charged sections of the torch. If the center insulator does
not provide adequate resistance, current which is in-
tended for the pilot arc may be dissipated into the torch
head, resulting in torch failure.
1. Remove the shield cup, tip, gas distributor, and elec-
trode from the torch.
Electrode
Torch Head Assembly
Figure 3-1 PCH-10 Torch Head Parts Removal
Firepower FP-18 Plasma Cutter
WARNINGS
PCH-10
Gas
Tip
Distributor
Standard
Shield Cup
A-02007
2. Disconnect the torch lead from the power supply to
isolate the torch from power supply circuits. Refer to
Appendix I for Leads connections.
3. Using an ohmmeter (set to 10K or higher), check for
continuity between the electrode seat (negative) and
the brass threads of the torch assembly. Infinite resis-
tance (no continuity) should be found. If there is con-
tinuity between the two, remove the torch head from
the lead and check the torch head separately.
B. Checking Torch Lead
If the torch head assembly is okay, check the torch lead
by measuring the resistance between the positive pilot
lead connector and the negative lead fitting. If continu-
ity is found, the insulation between the torch leads is
breaking down and the torch and leads assembly should
be replaced.
The lead cannot be replaced without replacing the
torch assembly as well.
If no continuity is found, check the resistance between
the negative plasma lead fitting and the electrode seat in
torch head. If no continuity is found, replace the torch
and leads assembly.
C. Checking Pilot and Switch Control
Wires
Check the pilot and switch control wires for continuity
from one end of the torch lead to the other. If no continu-
ity exists, replace torch and lead assembly.
D. Reassembling Torch and Leads
Replace parts as required, then recheck the torch head,
and lead connections to confirm proper measurements.
If each component is okay, reassemble torch and leads.
4.0 REPAIRS &
REPLACEMENT
PROCEDURES

4.1 General Information

• Failures identified on the Transformer/Inductor/
Chassis Assembly cannot be repaired - the entire
power supply must be replaced. Refer to the Parts
List for the catalog number for a replacement power
supply.
• The torch head, torch switch, and torch & leads as-
sembly are replaceable parts. The torch leads alone
are not serviceable; problems encountered in the leads
will require the torch & leads assembly to be replaced.
12
NOTE
Service Manual 0-2692