Service manual

1-34 June 21, 2004

GENERAL NP88 FLEX

Troubleshooting

Circuit Checks

Refer to the applicable receiver section in this publication for identification of the

components and test points referenced in the following sections.

Oscillator Warp Range

The oscillator wa rp range is the difference between the highest and lowest IF

frequencies obtained while varying the Oscillato r Trimmer Capacitor.

1. Ensure a battery with a minimum output of 1.3 volts is installed in the pager.

2. Refer to Tables 1-9 and 1-10 for lists of recommended test equipment.

3. Refer to the applicable schematic waveform and voltage information in the

appropriate supplement.

4. Ensure the pager is in self-diagnostic mode 5 (refer to "Self-Diagnostic Fea-

ture").

5. Monitor metering point M1 with a frequency counter.

6. Set the RF signal generator to the pager’s exact carrier frequency and at a

sufficient level to trigger the frequency counter.

7. Tune the Oscillator Trimmer Capacitor a nd note the highest and lowest IF

frequency displayed by the counter. The difference must be between 7 and 15

kHz.

Mixer Injection Voltage Measurement

1. Ensure a battery with a minimum output of 1.3 volts is installed in the pager.

2. Refer to Tables 1-9 and 1-10 for lists of recommended test equipment.

ACPB-930353-A

Figure 1-31. 10 dB Rise Measurement

First and second oscillator activities and injections must be observed using a

high-impedance probe.