Power Supply Voltage Test; Troubleshooting - Ametek 303B User Manual

5-6 | 303B Moisture Analyzer Manual
3. Adjust sample gas pressure to about 3.4 bar (50 psi) gauge.
4. Vary sample gas pressure between 1.4 and 6.9 bar (20 and 100 psi)
gauge and check that flow does not vary more than ±5 percent.
Power Supply Voltage Tests
1. Press POWER key (LED ON).
2. Disconnect the ribbon cable plug from power supply board connector
J2.
3. Measure the voltages shown in figure 4-3 on each J2 pin using small
clip leads. If any voltage is > ±10 percent, replace the power supply
board.
4. If all voltages are ok, connect the ribbon cable plug and do a:
• Cell Test to check the 50-volt supply. Unplug the cell at JP6. If the
displayed voltage is not between 47 and 53, replace the power
supply board.
• Electrical Test to check the 5-volt supply. If the displayed voltage is
not between 4.7 and 5.3, replace the power supply board.
• Output Test to check the 4 to 20-mA output. Disconnect the leads
from JP1-1 and -2 and attach a dc voltmeter in their place (+ to -1).
If the volt-meter does not read between 13 and 17, replace the cpu/
display board.

Troubleshooting

Troubleshooting Table 4-1 localizes a faulty assembly. It is not intended to
isolate a faulty component.
Memory Errors Er01 and Er02
Both these displayed errors are associated with the Analog Range, Alarm
Setpoint, Gain, Offset, and Factory Gain variable parameters stored in
electrically erasable read-only memory (EEPROM). EEPROM retains pa-
rameter values on power shut-down so they can be enabled on power-up.
A coding scheme — checksum — is stored with the data to make sure the
data does not change during storage.
On power-up, the stored parameters are read and checked against the
checksum. If there is a problem with checksum reading, read error Er01