b. For the rechargeable battery assembly (P/N 6025-1018), an accurate test of
battery charge condition requires that AC line power is turned off. If the TEST
switch is pressed with AC power on, the green BAT lamp should always light since
the charging circuit, which is on when AC power is on, provides a 28 volt potential
across the battery supply terminals. A red or red/green lamp indication may result
if battery supply is very weak, fully discharged, or defective. A battery protection
circuit in the rechargeable battery assembly automatically disconnects the supply if
the battery voltage is below approximately 19 volts in which case neither BAT lamp
would light during test and loss of synchronization occurs if AC power is off. For
an accurate test of battery condition, press the TEST switch with AC power off and
the BAT switch on and note the BAT lamp indications of step c.
The BAT lamp indications are as follows:
(1) Green BAT test lamp only lights:
Battery measures greater than 22 volts.
Conditions are acceptable for operation
on battery power.
(2) Green and red BAT test lamps
Battery measures between 18 and 22
volts. Conditions are marginal for
operation. Battery pack must be
charged soon (if rechargeable type)
or replaced (if non-rechargeable type).
(3) Red BAT test lamp only lights:
Battery measures less than 18 volts.
Battery pack must be replaced or re-
charged; or BAT switch is off.
5-27. BATTERY CHARGER ADJUSTMENT (For Battery Assembly P/N 6025-1018).
The battery charger circuit, located inside the rechargeable battery box, automatically
recharges depleted batteries and provides a floating trickle charge to maintain the
batteries in a fully charged state during normal AC line power operation of the TCS-
4B transmitter. Battery capacity and lifetime are dependent on the charging circuit
output voltage. A charging voltage that is too high can damage the batteries, and
too low a voltage does not maintain adequate charge in the battery cells. The battery
charger circuit is set at the factory for a trickle charge voltage of +28.2 VDC which
results in a 5 mA trickle charge current when connected to a fully charged battery
pack. (This voltage will vary depending on the state of charge of the batteries).
The battery charger circuit should not normally require readjustment. If adjustment
is required due to replacement or aging of components, adjust as follows:
Remove battery pack (6025-1018) from the 1024 unit.
Remove top cover of battery pack.
c. Carefully connect a +35 VDC (2V) external laboratory-type power supply to
the battery charger circuit card inside the battery box. The positive (+) output lead
of the power supply must connect to terminal E1 of the circuit card and the negative
(-) output lead must connect to terminal E 2 (ground).
d. Connect the positive lead of a digital voltmeter to TP1 and the negative lead
to E2 of the charger circuit card.