SCP SCIENCE DigiPREP HP, Руководство по обслуживанию

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KeyPad service manual
Rev.1.1 34
6.1.2 A/D power and connections

With the help of a multimeter, make sure that the A/D (U9) is powered
(see figure 22 for pin 15 and 16 location). If it is not powered up, then
the 5V regulator (U7) part is not functioning correctly.

If available, with help of a scope, verify that the Y1 component is
oscillating at the correct frequency, which is 4.9152MHz (see figure 22
for part location).
Figure 22: A/D, Oscillator and regulator location
Legend:
1. U9 pin 16
2. U9 pin 15
3. U7 (5V regulator)
4. Y1 (4.9152 MHz oscillator)
6.1.3 A/D conversion behavior

Before changing the A/D, make sure that all the external instruments
(sensors, probe, etc.) and interconnection cables are not broken.

Replace the A/D and verify if the system is heating up accordingly and
that the temperature feedback is correct.
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