Wahl ST2200 User Manual page 29

ST2200 Soldering Iron Tester User Manual
2. Apply steady and firm (but not heavy) pressure to the sensor.
3. If display indicates "1---" with or without the soldering iron on it, it may
indicate an open ST2200 sensor. First, make sure the Input Selector Switch is in
the "TIP TEST" position. If it is install new sensor and try again. If the sensor is
working properly, the unit should display room ambient temperature when in
TEMPERATURE mode with no iron touching the sensor. If problem persists,
ST2200 may be faulty and should be serviced by qualified technician or returned
to Wahl for evaluation and repair.
8.5.2 Troubleshooting - Millivolt Measurement Problems
If measurements are in doubt, connect a clip lead from the ST2200 sensor to
ground at the AC line. The display should indicate 0.00 to 0.10mV for a "zero"
input.
If it is out of this range, the ST2200 may need calibration or repair. Try
reconnecting the ST2200 AC cord at the AC line and try again. The contact
resistance of the ground connection at the AC line is not a major factor, but if it is
over 100 ohms, erratic readings may appear. Switch to the "RESISTANCE" and
measure the resistance of the soldering iron back to the AC line. If more than the
5 ohms or so is measured, there may be a problem with the ground in the
soldering iron or the AC line receptacle.
8.5.3 Troubleshooting - Resistance Measurement Problems
The contact resistance from the soldering iron power cord to the AC line and the
contact resistance from the ST2200 power cord to the AC line will cause most of
the indicated error in this measurement assuming the soldering iron itself is under
5.00 ohms.
Following are some suggestions for obtaining accurate readings or to solve
Resistance Measurement problems.
1. High or erratic readings - Remove the AC line cord and reconnect for both the
soldering iron and ST2200 and try again. If still high, connect the soldering iron
to the AC power receptacle on the ST2200 and measure again. If still high,
connect a clip lead from the ST2200 sensor to ground and verify that there is
resistance of no more than 0.10 ohms.
If the clip lead test is fine but the soldering iron test was high, it points to the
soldering iron as the problem.
2. Display always reads"1---". Replace the ST2200 sensor and try again with a
soldering iron or clip lead from ST2200 sensor to ground. If the display still reads
open, check the ground where the ST2200 line cord is plugged in. Sometimes the
AC receptacle ground clips break and a ground connection is not available even
though AC power is available to the ST2200.
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