Service Manual
Chapter 7 - Troubleshooting
Typical Voltage Values
7 - 11
3x3 UPS Troubleshooting
Issue 2 - November 2001
7.6 - Typical Voltage Values
The following table of values have been taken from a serviceable UPS and are intended to give a typical
reference when carrying out fault diagnosis.
Table 7-2
Typical Measured Voltage Values and LED indications
PCB
Test Point/LED Indication
Normal Value
Comment
3Ph TL Control Logic SE0072
TP2 (+ve) to TP3 (Ćve)
4.27V dc
Inverter feedback signal to U8 Level adjusted by P1.
TP4 (+ve) to TP5 (Ćve)
4.31V dc
Converter feedback signal to U9 Level adjusted by P2.
TP6 (+ve) to TP7 (Ćve)
4.28V dc
Static Switch feedback signal to U8 Level adjusted by P3.
TP9
Logic Low
NO MAINS OK signal from U12A.
TP10
2.49 Ć 2.29V dc
MAINS FREQ signal from U12B.
TP11
5.48V dc
TEMP ALARM signal from U14C (Active Low).
TP12
0.021V dc
MANĆBYP signal from U12D.
TP14
0.37V dc
MAINS PRESENT signal from U12F.
TP15
0.025V dc
NO BATTERY HIGH signal from U13A.
TP16
5.01V dc
BATTERY LOW signal from U13B.
TP17
0.016V dc
NO BATTERY PREALARM signal from U13C.
LED LD1 (green)
ON
UPS Normal (OFF indicates an over temperature ST1, a DC offset
condition or PCB power failure)
Auxiliary DCĆDC Converter SE0070
U2A pin 1
8.88V dc
Battery voltage monitor.
R36
5.59V dc
VMAX level adjustment (P1) sets battery high level 500V.
R37
7.89V dc
VMIN level adjustment (P2) sets battery low level 320V.
R39
7.53V dc
PREALARM level adjustment (P3) 350V.
Molex Connector PM2 Pin 1
16.83V dc
+15V supply to Inv. driver feedback PCB.
Molex Connector PM2 Pin 2
7.68V dc
+7.5V supply to Inv. driver feedback PCB.
Molex Connector PM2 Pin 3
0V
Ground.
Molex Connector PM2 Pin 4
15.33V dc
Battery high output to Inv. driver feedback PCB.
Molex Connector PM2 Pin 5
0.616V dc
Battery low output to Inv. driver feedback PCB.
Molex Connector PM2 Pin 6
15.47V dc
Battery Prealarm output to Inv. driver feedback PCB.
Inverter Driver Feedback SE0071
R66
6.43V dc
Reserve Bypass Vmin level adjustment (P2)
R69
5.54V dc
Reserve Bypass Vmax level adjustment (P1)
R149
9.53V dc
Temperature alarm reference adjustment (P3)
LED LD1
OFF
ON indicates incorrect phase rotation.
LED LD2
OFF
ON indicates DC Offset unbalanced load.
Battery Charger SE0074
Note: No voltage measurements can be carried out safely on this PCB.
LED LD1
FLASHING
FLASHING indication when float charging battery.