Servicing the at30, Symptom probable cause recommended action – Exide Technologies Section 94.40 User Manual
Page 58

SERVICING THE AT30
54
SYMPTOM PROBABLE
CAUSE
RECOMMENDED ACTION
Input current 
too high 
1. Wrong ac 
input voltage, or 
T1 wired 
incorrectly 
2. Defective 
rectifier bridge 
 
 
3. Defective T1
1. Be sure the T1 primary taps are wired correctly for your input 
voltage. See 
Changing Transformer Taps, Section 1.6. The actual
ac input voltage must be at least 88% of the rated value for the 
AT30 to produce full output power. 
2. Disconnect the wire harness plug from connector J26 on the 
top of the Gate Driver pc board (A15) and restart the AT30. If you 
are able to measure output current, one of the SCRs is defective. 
Replace the rectifier module(s) (A16) as needed. 
3. Test by disconnecting wires #
7, 8 & 9 from the transformer
secondary taps and wires #
42, 43, 44, 45, 35 and 36 from the
tertiary taps. If ac input current is still too high, replace T1.
Output ripple 
voltage too 
high 
1. AT30 is 
unfiltered 
2. Battery is 
disconnected or 
defective 
3. Battery too 
small for AT30 
rating 
 
4. Defective filter 
capacitors C1 
and/or C2 
1. Verify by checking the data nameplate against the ordering 
code on page i. Order and install the dc filter option if desired. 
2. Be sure battery is connected. Inspect battery according to the 
manufacturer's instructions. 
 
3. Check the measured ripple against the specification for your 
AT30 model on page 64. The ripple rating is for a battery whose 
Ampere-hours are four (4) times the charger Ampere rating. For a 
smaller battery, ripple voltage may be higher. 
4. Test with capacitance meter and replace as needed.
AT30 very 
noisy 
1. Loose 
hardware or 
enclosure panel 
2. Defective 
rectifier bridge 
1. Check and tighten all component mounting hardware and panel 
hardware. 
 
2. Use a clamp-on ammeter to measure the current in wires # 
7, 8
&
9, between T1 and the rectifier modules. If it less than 50% of
the dc output current, one of the SCRs or diodes is defective. 
Replace the rectifier module(s) (A16) as needed. 
Meter 
readings are 
erratic 
1. Defective or 
disconnected 
battery 
 
 
2. Defective 
scaling resistor 
R4 or R14 
 
 
3. Defective 
Main Control 
board A1 
1. Turn off the AT30. With a light dc load connected to the battery, 
be sure each cell reads the nominal cell voltage (2.0V for lead-
acid / 1.25V for Ni-Cd). Restart the AT30. Each cell should now 
read approximately the nominal Float voltage (2.2V for lead-acid / 
1.35V for Ni-Cd). 
2. See page 61 of Section 3.5. Locate R4 and R14 on the Gate 
Driver pc board (A15). Remove one end of each resistor and 
measure its value with an Ohmmeter. See the table in Section 3.6 
for resistance values. If either resistor is not within 1% of the 
specified value, replace R4 and/or R14 as needed. 
3. If the output voltage is constant, but the front panel meter is 
erratic, replace the Main Control board (A1). 
