SERVICING THE AT30
53
SYMPTOM
PROBABLE
CAUSE
RECOMMENDED ACTION
Output
voltage does
not agree
with front
panel meter
1. Temperature
compensation
probe is
installed
2. Circuit board,
or another
component may
have been
replaced
3. R4 or R14 is
defective, or
wrong value
4. Defective
Main Control
board A1
1. If the optional temperature compensation probe is installed,
the output voltage may be different from the selected float or
equalize voltage. The difference in the voltages depends on
the probe temperature. The front panel meter always displays
the selected voltage as if the battery were at 77° F / 25° C.
2. Recalibrate the voltmeter accuracy as described in Section
2.3.7.
3. See page 61 of Section 3.5. Locate R4 and R14 on the
Gate Driver 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.
4. Turn off both front panel circuit breakers (CB1/CB2), or turn
off ac and dc power externally, if the AT30 does not have
breakers. Wait one minute before returning the dc connection,
followed by the ac connection. If the charger still has the
wrong output voltage, replace the Main Control board (A1).
Charger
never
reaches float
(or equalize)
voltage
(within 1%)
1. Current limit
set too low
2. Defective
battery or dc
load, or load is
too great
3. Wrong ac
input voltage, or
voltage too low,
or T1 wired
incorrectly
4. Defective
rectifier bridge
5. Defective
Main Control
board A1
1. If the AT30 is not in the Edit mode, press the
EDIT/ENTER
key five times, until the meter display flashes the current limit
value (in Amperes). If the current limit is less than 110%,
adjust it to 110% as described. See
Setting the Current Limit
Value
, Section 2.3.5 for details.
2. Check each cell of the battery. If one or more cells are
shorted, the AT30 may not be able to reach the Float voltage.
You may have the same problem if the normal load current is
more than the rated output current of the charger.
3. Be sure the main transformer (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.
4. 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.
5. Turn off both front panel circuit breakers (CB1/CB2), or turn
off ac and dc power externally, if the AT30 does not have
breakers. Wait one minute before returning the dc connection,
followed by the ac connection. If the charger output current is
below the current limit value, but it still has the wrong output
voltage, replace the Main Control board (A1).
Summary of Contents for AT30 SERIES
Page 99: ......
