No Leds And No Output - Ablerex 3 MS series User Manual

5.5 No LEDs and No Output

Check Items
Power Devices defective, AC or DC fuse is burn
The working voltage of the control board is out
of order.
CPU is down.
FIG. 5.5
Trouble-shooting
Please see table 5.3 and 5.4 .
1.Please check the circuit shown in fig.5-2.
2.Cut off the Utility. Remove the control board.
Supply a 72Vdc to CN10(+) and CN9(-) by a DC
Power supply, connect CN4 to the main switch.
Push on the main switch and to see if DC
POWER, i.e. VDD(17.5V), VCC(12V) and +/-
5V is normal.
3.Check if Q9, Q16, Q13, Q14, D22, D21 and U8
Is normal.
4. Check if any abnormal output signal of the U9.
If the DC POWER is normal, the CPU could be
Down. Remove the battery harness from the
UPS and re-connect it back to its position.
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