STANDBY BATTERY SUPPLY TEST

TM 11-5820-917-13

points. To measure DC voltages in the 4028, it is necessary to remove the unit

cover and the four screws which secure the 2A1 and the 2A2 assemblies to the

chassis plate. The two assemblies are then lifted to allow access to the assembly

test points. To measure DC voltages in the 6025, it is necessary to remove the

unit cover. The assembly test points are readily accessible without further dis-

assembly. Note that the AC ripple for all regulated supplies measures less than

10 mV peak-to-peak.

5-14. Voltage variations from the normal 115 or 230 VAC input can be accommo-

dated by changing connections on the terminal board 2A3TB 1 located on the 4028

chassis plate. The unit cover must be removed to allow access to the terminal

board. Upper limits of 120 (or 250) VAC can be tolerated using the same factory

wiring as for 115 (or 230) VAC. If the line voltage approaches 105 (or 220) VAC,

turn power off, and transfer the connection on 2A3TB 1 pin 1 to 2A3TB 1 pin 2

5-15. STANDBY BATTERY SUPPLY TEST. Two different types of standby battery

assemblies are used in the RCS- 4B. Some receivers have a non-rechargeable

battery assembly (part number 6025-1008) that uses standard D-cell batteries.

Other receivers have a rechargeable battery assembly (part number 6025-1018)

that includes an integral charging circuit and uses sealed lead acid cells. Con-

ditions for testing the charge of the battery supply differ between the non-

rechargeable and rechargeable assemblies. These different conditions are noted

in steps a and b below. The test results as defined in step c apply to the test

of non-rechargeable and rechargeable assemblies.

For the non-rechargeable battery assembly (P/N 6025-1008), a test may be

conducted at any time during operation with AC line power on or off and the BATT

switch on. Pressing the TEST pushbutton switch on the 6025 front panel initiates

the test and the BATT lamps light to indicate the charge condition of the battery

supply as described in step c below.

b. For the rechargeable battery assembly (P/N 6025-1018), an accurate test of

battery charge condition requires that the AC line power is turned off. If the

TEST switch is pressed with AC power on, the green BATT 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 indi-

cation may result if battery supply is very weak, fully discharged, or defective.

A battery protection circuit in the rechargeable battery assembly automatically dis-

connects the supply if the battery voltage is below approximately 17 volts in which

case neither BATT 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 BATT switch on and note the BATT lamp

indications of step c.

The BATT lamp indications are as follows:

(1) Green BATT test lamp only lights:

Battery measures greater than 22

volts. Conditions are acceptable for

operation on battery power.

5-6