10
CORRECTIVE MAINTENANCE
Your TJ-70 requires no special maintenance other than being kept clean. The
heater bore and the heater assembly set screw which secures the tip must be
kept free of oxidation and debris in order to maintain the proper tip to ground
resistance. Periodically inspect the cable, connector and handpiece itself for
evidence of physical damage. Do not use a handpiece with a damaged cable.
Refer to Table I (TJ-70 Heater Assembly Checkout Procedures) and the
Connector Plug illustration below for information on troubleshooting most
handpiece problems. Table II lists the common handpiece parts.
SYMPTOM
CHECKOUT PROCEDURE
CAUSE
SOLUTION
No heat
Check resistance - Pin 2 to Pin 5.
If the resistance is greater than
7 ohms -
Open Heater
Replace
Heater
Assembly
Check resistance - Pin 3 to Pin 6.
If circuit reads open -
Open Sensor
Replace
Heater
Assembly
Handpiece
overheating
Check resistance - Pin 3 to Pin 6.
Resistance should be 110 ohms. If
circuit reads less than 105 ohms -
Shorted
Sensor
Replace
Heater
Assembly
No Ground
on Tip
Check resistance - Pin 4 to a NEW
Tip. Resistance should be less than
2 ohms. If not -
Oxidation
buildup in
Heater Bore
Clean Heater
Bore using
appropriate
wire brush
Defective
Heater
Replace
Heater
Assembly
T
ABLE
I. TJ-70 H
EATER
A
SSEMBLY
C
HECKOUT
P
ROCEDURES