Service manual

debug the corresponding circuit. If unfortunately, both modes are incorrect, two possible
circuits should be check: Bus feedback loop (on PSDR) and auto-balance circuit (on
CNTL).
6.4 Test And Finish
After replace all defected components on power stage (PSDR), following test the steps can
be adopt to verify the repair result and the reliability of the UPS.
1. Connect all of boards, cable, and connector right to place.
2. Check the Wiring
3. Apply DC Power from power source with current limitation function to the BAT terminal on
the PSDR, the voltage of the DC power should be 96-110Vdc/3 Amp (limited current) for
2/3K UPS, 36~41Vdc/3Amp 1K UPS
4. Press the ON-switch on front panel for 2 seconds, you will see "current limit" for a short
time on the DC power supply for about only 2 seconds, then UPS should be DC started, If
UPS does not start successfully. Please try diagnosing procedure again.
5. If UPS does not start up for several trying or DC power supply is on current-limit state
continuously, there must be some defected components exists. Please follow
trouble-shooting chart to debug again.
6. Stop the UPS; apply AC mains to the UPS module. Try on the UPS. If fail you may have
start one new round of trouble shooting
7. Check and adjust Charging Voltage
8. Check the output voltage waveform and DC-offset voltage, at no-load and full load
condition.
9. In most case result of step7, 8 can represent whether product in normal condition, If
possible, however, for more reliability, perform quick check follow procedure shows in
table would help in know the UPS situation in detail.
Tab.
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