BASEWEST
Operating & Maintenance Manual
Model TS-420 Test Set
Page 3 of 10
25-60-41
24 Jan 2002
2.0 Theory of Operation
2.1 General
The Model TS-420 provides for voltage testing of escape slide lighting system battery
packs, and electrical current testing of escape slide lighting harnesses. A special interface
connector provides for full system test of an installed battery pack and lighting harness
system through a mating test connector found on most battery packs. The voltmeter and
ammeter modes are selected by a Mode Selector (rocker switch) mounted on the
instrument panel. The voltmeter mode is provided with a multi-value resistive load bank
that can be selected by a panel-mounted Load Selector (rotary switch). The ammeter
mode measures current through the lighting harness provided by a built-in regulated 5VDC
power supply. Tests are initiated through a guarded Press-To-Test switch
2.2 Voltmeter Mode
The voltmeter mode is used to test battery condition. The voltmeter mode is selected
when the Mode Selector switch is in the VOLTMETER position. In this mode, the Press-
To-Test switch is a momentary push button - the instrument is ON only so long as the
switch is depressed. When the test switch is pressed, the Self-Test indicator illuminates
GREEN and the voltage of a connected battery pack is displayed on the digital meter. The
battery under test is subjected to the resistive load selected by the panel-mounted rotary
switch. Positions A through F are resistive loads exactly matching those of test equipment
described in slide manufacturer manuals; a NO LOAD position is offered to allow open
circuit voltage testing of the battery. The Battery Status indicator is not active in this mode.
2.3 Ammeter Mode
This mode is used to measure the amount of current being drawn through the lighting
harness under a 5VDC regulated input. The ammeter mode is selected when the Mode
Selector switch is placed in the AMMETER position. Activating the Press-To-Test switch
in this mode provides 5VDC regulated power to the output connectors, and initiates a 20
second timer. The power supply and meter turn off automatically approximately 20
seconds after the test switch is pressed. The device will remain on and active so long as
the momentary switch is pressed in, but will return to the OFF condition if the switch is
released after the initial 20 second period. In the ammeter mode, the Self-Test indicator
illuminates GREEN, indicating that the internal power supply is providing 5.0 VDC and the
unit is OK for test; if the Self-Test indicator illuminates RED, the test set must be removed
from service and recharged. The Battery Status indicator, if illuminated, indicates that the
internal battery pack is low and recharging is required.
NOTE
: The device is OK for test and can continue to be used in either mode so long
as the Self-Test illuminates GREEN when the Press-To-Test switch is activated.