Tweco Max 300 w-Merlin 6000GST - Manual (Page 36)

SERVICE 5-6 Manual 0-2642
Plasma Lead
Coolant Return (-) Lead
(LH Threads)
Secondary (+)
Lead
Coolant
Supply Lead
A-01524
Figure 5-6 Torch Head Removal
8. Remove the rigid insulator from the old Torch
Head Assembly from between the layers of
estermate paper.
9. Unscrew and remove the torch adapter from the
torch head assembly.
B. Reassembling Machine Torch Assembly
1. Slide the torch adapter down over the leads and
screw the adapter securely onto the back of the
torch head assembly.
2. Slide the rigid insulator between the layers of
estermate paper on the replacement Torch Head
Assembly (see note).
NOTE
Over a period of time there may be a breakdown of
the estermate paper causing the Torch Head to short
out if the rigid insulator is not installed.
Two Layers Of
Estermat Paper
Rigid Torch
Leads Insulator A-01577
Figure 5-7 Rigid Insulator Installation
3. Secure the rigid insulator inplace with electrical
tape.
4. Connect the plasma, secondary (+), coolant sup-
ply, and coolant return (-) connectors.
5. Secure leads and tubing with single layer of elec-
trical tape.
6. Slide the positioning tube down over the leads
and thread it into the torch adapter on the torch
head assembly.
7. Connect the gas solenoid control cable to the gas
control solenoid assembly.
8. Connect the plasma hose, #3 Fuel B, to the gas
control solenoid assembly.
9. Connect the plasma supply hose, #3 O2B, to the
gas control solenoid assembly.
10. Connect the preflow supply hose, #4 JIC, to the
gas control solenoid assembly.
11. Install the front end torch parts.
5.07 Torch And Leads
Troubleshooting
A. General Information
Failures in the Torch and Leads can be isolated to the Torch
Head or Torch Lead components. To properly isolate the
failed part requires the use of an ohmmeter and a Hi-Pot
Tester.
WARNING
The use of a Hi-Pot Tester should be performed only
by a qualified electronic technician.
In the Torch Head the center insulator separates the nega-
tive and positive charged sections of the torch. If the cen-
ter insulator does not provide adequate resistance, cur-
rent which is intended for the pilot arc may be dissipated
into the torch head, resulting in torch failure.
In the Torch Leads the negative and positive leads are
isolated from each other. If there is not adequate resis-
tance between the leads then torch failure may occur.
B. Quick Check Procedure
This quick check will identify major isolation failures in
the Torch Head or Torch Lead components using an ohm-
meter.
The actual assembly and consumables may vary for dif-
ferent torches but the basic procedure is the same for all
torches. Make the quick check on the Torch Head and
Leads per the following procedure: