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Chapter 2 Service
Troubleshooting the Counter
Assembly-Level Service Guide 2-45
2
Troubleshooting the Counter
Power Supply Check
WARNING HAZARDOUS VOLTAGES ARE ON THE POWER SUPPLY
ASSEMBLY. ONLY SERVICE TRAINED AND QUALIFIED
PERSONNEL SHOULD PERFORM THE FOLLOWING
PROCEDURE.
1 Remove the power cord from the back of the instrument to
disconnect the Counter from the power source.
2 Remove the cover as described in Chapter 3.
NOTE
A4 AC Power Supply Assembly is fused for safety reasons. It is assumed
that if the fuses are blown, then damage has occurred to the power supply
which will make it unreliable. Do not attempt to repair the power supply.
3 Connect the Counter to the power source.
The fan should begin to operate as soon as power is supplied. If the fan
does not operate, replace A4 AC Power Supply Assembly.
Refer to Chapter 3, “Replacing Assemblies,” in this service guide if you
need to remove or replace an assembly.
After replacing the power supply assembly, perform the appropriate
calibration procedures in this chapter.
4 Connect the negative lead of a voltmeter to the chassis and verify
that the voltages in Table 2-4 match the voltages measured on
connector J18 of A1 Motherboard Assembly. See Figure 2-9 for
illustration of J18 viewing from the bottom of the Counter.
CAUTION BE CAREFUL to NOT short the positive-side lead of the voltmeter to the
chassis when probing at the testpoints shown in Figure 2-9.