Corrective Maintenance; Power Source; Handpieces - Pace ST 25 Operation And Maintenance Manual

temperature is off by more than ±15°C, the handpiece may require maintenance.
Recheck the temperature using a second handpiece.
4. Carefully lock the Variable Temperature Control in position by tightening the inner set
screw (closest to front panel).
5. Loosen the outer set screw on the Variable Temperature Control
knob (furthest from front panel) using the Temp. Locking Key
(hex key) supplied with the system. Position the knob with the
pointer aligned to match the temperature indicated on the
temperature meter. Secure the knob in position by tightening the
outer set screw.
6. Loosen the inner set screw to unlock the Variable Temperature
control if adjustment of operating tip temperature is desired.

Corrective Maintenance

Power Source

Most malfunctions are simple and easy to correct. Refer to Table 3.
Symptom
No power to
system
Handpiece will
not heat

Handpieces

The following "Heater Assembly Checkout Procedures" (Table 2) is applicable to all PACE
SensaTemp handpieces used with the ST 25 or ST 35 system except for the TT-65 and DTP-80
handpieces. Refer to the applicable manuals for troubleshooting procedures pertinent to these
handpieces.
Perform the procedures with the handpiece heater at room temperature. If the heater is warm,
resistance readings will be different from those shown in Table 2. 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.
Problem
Handpiece does not heat
Handpiece Overheating
Fuse blows when power
source is turned on
©2001 PACE Inc., Laurel, Maryland
All Rights Reserved
Probable Cause Solution
Blown Fuse Check handpiece using table 4. Replace the fuse
(located in the AC Receptacle Fuse Holder) with
one of the same rated value (see Table 6, Spare
Parts)
Defective Heater See Table 4.
Power Source Contact PACE
Malfunction
Table 1: Power Source Corrective Maintenance
Checkout Procedure
Check resistance: Pin 2 to
Pin 5. Refer to heater
specifications below if
resistance is high, see
Solution
Check resistance: Pin 3 to
Pin 6. If circuit reads open,
see Solution
Check Resistance: Pin 3 to
Pin 6. Resistance should
be 110 ohms. If resistance
is less than 105 Ohms, see
Solution
Check resistance: Pin 2 to
Pin 5. Refer to heater
specifications below if
resistance is low, see
Solution
Cause
Open Heater
Open Sensor
Shorted Sensor
Shorted Heater
Solution
Replace Heater Assembly
Replace Heater Assembly
Replace Heater Assembly
Replace Heater Assembly
and Fuse
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