Chapter 2 Service

Troubleshooting the Counter

 

 

Troubleshooting the Counter

 

 

Power Supply Check

 

 

HAZARDOUS VOLTAGES ARE ON THE POWER SUPPLY

WARNING

 

 

 

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 2-4match the voltages measured on

 

 

connector J18 of A1 Motherboard Assembly. See Figure 2-9for

 

 

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.

2

Assembly-Level Service Guide

2-45