Sentry Model HM-535 Power Supply
Installation and Service Manual
430-535 0104 © 2004 Heritage MedCall, Inc.
5
supply's controller can be reset by: 1. disconnecting the battery, and 2. cycling the
AC power Off for 10 seconds.
If that does not restore data communication, the data line wiring to the power supply
is probably bad.
A spare host panel, set to address code 63 can be temporarily connected to check
the data line.
If the data wires are functional and the power supply does not communicate, the
data driver and microcomputer will require replacement. These components are
installed in sockets for easy replacement. Replace components labeled U9 & U10
on the lower right PCB. Be certain to install the components in the proper direction
and assure that all pins insert into the proper holes. Contact Sentry for service parts.
3.4
AC POWER
If all of the indicators are off, the supply has lost power and the battery is
disconnected or drained.
Check the AC power to the supply. Test the AC terminal block for 117V AC.
3.5
BATTERY
The LOW BATT indicator will light when the battery gets discharged below 10V or
if the battery fuse is open.
Check the battery fuse on the bottom of the PCB. If necessary replace with another
fuse.
For continued protection: replace fuse with only the same type and rating.
Check the battery voltage when connected to the power supply. It should be above
13 volts. Check the battery voltage when the test button is pressed. If the battery
voltage drops to less than 9 volts, the battery is no good and must be replaced.
When a new battery is installed, it can be checked by manually pressing the TEST
button. The LOW BATT indicator will go Off.
The CHG TRBL LED normally lights for 5 seconds when the battery is being tested.
This test inhibits the battery charger during the battery load test.
