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13.2 Calibration Procedure (See Figure 13-1)
13.2.1 Equipment Required
1. Digital Voltmeter, Fluke 8600 41/2 digit or equivalent.
2. Decade resistance box with a range to 30K and resolution to one
ohm. Accuracy required can be determined by using the thermistor slope at
60°C where an error of 1 ohm is equivalent to .01°C.
13.2.2 Calibration
1. Connect DVM(+) to TP2 and (-) to TP1. Turn on power switch and
adjust R15 for a DVM reading of 2.110 ±.002 volts. This sets the low battery
indication point at a battery voltage of 5.5 Volts.
2. Connect the decade resistance box to the unit to be calibrated by
using a cable length of approximately five feet of 22AWG wire and a
Switchcraft #250 plug connector.
3. Set resistance to 29,490 ohms and adjust R5 for a display read-
ing of 0.00°C (32°F).
4. Set the decade box to a resistance of 2760 ohms and adjust R13
for a display reading of 60.00°C (140.00°F).
5. Set the decade box to a resistance of 12,260 ohms and check the
unit for a correct display reading of 20.00°C or 68.00°F.
6. Repeat steps 3, 4 and 5 as necessary for best calibration.
14.0 392M TROUBLE-SHOOTING AID
14.1 Scope
This section describes basic diagnostics to find the majority of the problems
with malfunctioning 700M units.
Equipment Required:
1. Decade Resistance Box
2. 4- Digit DVM, Fluke 8600A or equivalent.
3. Oscilloscope.
4. Power supply, Power/mate BPA-10c or equivalent.
14.2 Procedure
Make certain that the 700M unit experiencing the problem has been properly
set-up, per Section 13.0, before proceeding to this section.
Figure 13.1. 700M Circuit Board Layout