Datron PRC-PS, Руководство оператора, Страница: 31 / 45

5: Maintenance
PRC-PS-MS 5-7
1. Measure the DC voltage at the rectifier bridge BR1 (+) terminal. It
should be 20 Vdc ± 3.0 Vdc for AC operation; if not, refer to the AC
Power Supply section on page 5-9 . For DC operation the DC voltage at
the rectifier bridge should be about 1 Vdc less than the DC supply
voltage; if not,
refer to the Reverse Current Protection section on page
5-8 .
2. Observe the front panel status LEDs. If none of them is lit, refer to the
Status LEDs section on page 5-10 .
3. If the CHARGING LED is lit, skip to step 7.
4. With more than 6 Vdc across the capacitor, the FAULT LED should now
be lit. On the IC, measure the DC voltage at pin 7. If it is more than
100 mV, replace the IC.
5. On the IC, measure the DC voltage at pin 12. If it is less than 3 Vdc,
check the resistive divider (R20, R21) at pin 12.
6. On the IC, check for a short circuit at pin 11 (pin 11 should be high).
This output pin drives the FAULT LED through a series resistor on the
display board. If the FAULT LED is not lit, replace the IC.
7. The CHARGING LED should now be lit. If more than one LED is lit,
refer to the Status LEDs section on page 5-10 .
8. On the pass transistor Q3, measure the voltage from the emitter to the
base. If it is between 0.6 Vdc to 1.0 Vdc, skip to step 9. If the voltage is
below 0.6 Vdc, replace the IC. If the voltage is above 1.0 Vdc, replace
the transistor.
9. Using an ohmmeter (or a diode checker), measure the forward and
reverse resistance of the IN5400 (D5) series diode. If the forward
resistance is less than 10 ohms and the reverse resistance is very high
(mega ohms), the diode is okay; replace the pass transistor; if not,
replace the diode.
Bulk Charging
Current
Regulation This section assumes a failure in the DC Current Check section on page 5-2 if
the CHARGING LED does not light up.
1. If the DC current is okay, but the CHARGING LED is not lit, refer to the
Current Source section on page 5-6 .
2. Measure the DC voltage across the 0.22 ohm current sense resistor R23.
If it is not 0.25 Vdc ± 0.02 Vdc, refer to the Status LEDs section on page
5-10 .
3. Turn off the power and measure the resistance of the 0.22 ohm resistor
R23. If it is not within 5% tolerance, replace the resistor.