SBS AT10.1 SERIES Operating And Service Instructions Download Page 60

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SERVICING THE AT10.1

SYMPTOM

PROBABLE

CAUSE

RECOMMENDED ACTION

Input current
too high

1. Wrong ac
voltage, or Vac
too low, or T1
mis-wired

2. Defective
SCR module

3. Defective
Transformer

1. 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.

2. Disconnect the twisted pair wires #

51/52

and #

53/54

from the

SCR (Q1/Q2) gate lead terminals. Note the original polarity so
wires can be replaced with the same orientation. Restart the
AT10.1. If you are able to measure output current, one of the
SCRs is defective. Replace SCR modules (Q1/Q2) as needed.

3. Test by disconnecting secondary wires from T1-X1, T1-X5, T1-
Y1 and T1-Y2. If ac input current is still too high, replace the main
power transformer (T1).

Output ripple
voltage too
high

1. AT10.1 is
UN-filtered

2. Battery is
disconnected or
defective

3. Battery too
small for charger
dc current rating

4. One or more
defective dc filter
capacitors

1. Verify by comparing model number on data nameplate decal
against the ordering code on the inside front cover of this manual.
If necessary, order and install dc filter field kit.

2. Confirm battery, which lowers ripple, is connected. Inspect
battery according to the manufacturer's instructions.

3 Measure ripple voltage on the dc output and compare the value
against the specification for your AT10.1 model on page 70. The
listed ripple rating is for a battery Ampere-hours rating which is
four (4) times the charger Ampere rating. For a smaller battery,
ripple may be higher.

4. Shut down the AT10.1 and wait several minutes to allow
capacitors to discharge. Open the AT10.1 and locate the blue
cylindrical electrolytic filter caps. Test each with a capacitance
meter. Replace dc filter capacitors (C1 and/or C2) as needed.

AT10.1 very
noisy

1. Loose
hardware or
enclosure panel

2. Defective
SCR module

1. Open the AT10.1 front panel door. Check and tighten all
internal component mounting hardware. Close and secure the
front panel. Check and tighten all external enclosure hardware.

2. Use a clamp-on ammeter to measure current in wires #

and

, 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.

Meter
readings are
erratic

1. Defective or
disconnected
battery

2. Defective or
wrong value
scaling resistor
(R4 or R14)

3. Defective
Main Control PC
Board (A1)

1. Shut down the AT10.1. With a light dc load connected to the
battery, confirm each cell reads the nominal cell voltage (2.0V for
lead-acid or 1.25V for Ni-Cd). Restart the AT10.1.

Each cell should now read the nominal Float voltage (2.2V for
lead-acid or 1.35V for Ni-Cd).

2. 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 scaling resistors (R4 and/or R14) as
needed.

3. If the measured dc output voltage is constant, but the front
panel meter display reading is erratic, replace the Main Control
PC Board (A1).