20
Corrective Maintenance
Handpieces
The following “Heater Assembly Checkout Procedures” (Table 4) is applicable to
all PACE SensaTemp handpieces used with the ST 85 system except for the TT-
65 and DTP-80 handpieces. Refer to the applicable manuals for troubleshooting
procedures pertinent to that handpiece.
Perform the procedures with the handpiece heater at room temperature. If the heater
is warm, resistance readings will be different from those shown. Disconnect the
handpiece from the power source. Use a meter to check resistance across the
handpiece connector plug pins as outlined in the “Checkout Procedure” column.
Table 2. Heater Assembly Checkout Procedures
Connector
Plug Pinouts
Symptom
Checkout Procedure
Cause
Solution
Heater Specifications
Handpiece
does not
heat.
Check resistance - Pin 2 to
Pin 5. Refer to "Heater
Specifications" column.
If resistance is high - -
Open Heater
Replace Heater
Assembly.
P S - 8 0
SX-80
SX-70
TP-65
TJ-70
= 8-10 ohms
= 8-10 ohms
= 8-10 ohms
= 9-11 ohms
= 6 - 8 ohms
Check resistance - Pin 3 to
Pin 6. If circuit reads open -
-
Open Sensor
Replace Heater
Assembly.
Handpiece
overheatin-
g; LED off.
Check resistance - Pin 3 to
Pin 6. Resistance should be
110 ohms. If resistance is
less than 105 ohms - -
Shorted Sensor
Replace Heater
Assembly.
Fuse blows
when unit is
turned on.
Check resistance - Pin 2 to
Pin 5. Refer to "Heater
Specifications" column. If
resistance is low - -
Shorted Heater
Replace Heater
Assembly & Fuse.
No Ground
on Tip.
Check resistance - Pin 4 to
a NEW Tip. Resistance
should be less than 2 ohms.
If not - -
Oxidation in
Heater Bore.
Clean Heater
Bore using
appropriate wire
brush.
Defective
Heater
Replace Heater.
