SBS AT10.1 SERIES, Operating And Service Instructions

Page: 59 / 104

SERVICING THE AT10.1
53
SYMPTOM
PROBABLE
CAUSE
RECOMMENDED ACTION
Output
voltage does
not agree
with front
panel meter 1. Temperature
compensation
probe is
installed
2. Components
may have been
replaced
3. Defective or
wrong value
scaling resistor
(R4 or R14)
4. Defective
Main Control
PC Board (A1)
1. If the optional temperature compensation probe is installed,
the output voltage may be different from the selected float or
equalize voltage. See Section 1.11, Step 11. The difference
in 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. If the Main Control PC Board (A1), or any other electrical
component, has recently been replaced, recalibrate the digital
dc meter as described in 2.3.7.
3. On the back of the front panel, locate R4 and R14 on the
Gate Driver PC Board (A11). Remove one end of each
resistor and measure its value with an Ohmmeter. Refer to
the table in Section 3.6 for values. If either resistor is not
within 1% of the specified value, replace the scaling resistors
(R4 and/or R14) as needed.
4. Turn off (open) both front panel breakers, or lock out ac and
dc power externally if the AT10.1 has fuses only. Wait 60
seconds. Restart by restoring dc power
first , followed by ac
power second. If the AT10.1 still displays or outputs the wrong
output voltage, replace the Main Control PC Board (A1).
AT10.1 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
voltage, or Vac
too low, or T1
mis-wired
4. Defective
SCR
5. Defective
Main Control
PC Board (A1)
1. If the AT10.1 is not in Edit Mode , press the EDIT/ENTER
key six (6) times, until the meter display flashes the Current
Limit value (in Amperes). If the Current Limit is less than
110%, adjust it up to 110% as described. See Section 2.3.5,
Setting the Current Limit Value , for details.
2. Check each cell of the battery. If one or more cells are
shorted, the AT10.1 may not be able to reach the Float
voltage. You may have the same problem if the normal dc load
current is more than the rated output current of the AT10.1.
3. Confirm the primary taps (T1-H#) are wired correctly for
your input voltage. See Section 1.6,
Changing Transformer
Taps . The actual ac input voltage must be at least 88% of the
rated value for the AT10.1 to produce full output power.
4. Use a clamp-on ammeter to measure current in wires # 5
and # 6 , between the transformer (T1) and SCR modules
(Q1/Q2). If it is less than 50% of the dc output current, one of
the SCRs is defective. Replace SCR modules (Q1/Q2) as
needed.
5. Turn off (open) both front panel breakers, or lock out ac and
dc power externally if the AT10.1 has fuses only. Wait 60
seconds. Restart by restoring dc power
first , followed by ac
power second. If the AT10.1 output is below the Current Limit
value, but it still has the wrong output voltage, replace the
Main Control PC Board (A1).