Tait T800 SL2 25W, Service Manual

Page: 328 / 383

F2.2 Power Supply Description
M8SL2-00-002-812
© Copyright Tait Electronics Limited August 2004. All rights reserved.
2.1.1 PSU Module
The PSU module used in the T800-23-0011 power supply has over temperature, current
overload and overvoltage protection. Refer to Section 1.2 for specification details.
Overvoltage applied on the module’s output will cause the module to shutdown. To
reset the module, remove the mains supply to the T800-23-0011, allow 30 seconds for
charges to leak away, and then reconnect the T800-23-0011.
The module is protected from current overload by a voltage foldback method. If the
load on the output starts drawing more current than the specified maximum, the volt-
age will start dropping away. This condition will recover automatically when the load is
removed or returns to normal.
Over temperature will cause the module to shutdown. It will recover automatically
when it has cooled down to an acceptable operational temperature.
Caution: Correct mounting of the T800-23-0011 power supply is important: Refer to
Section 3.3 for ventilation guidelines. Ignoring these conditions may cause
the module to overheat, and consequently, to shut down.
2.1.2 Internal Loom
Mains power to the PSU module is supplied via an IEC plug on the rear panel and then
filtered by a ferrite bead (shown in Figure 2.1). The mains ground line is filtered by a fer-
rite bead and then connected to the T800-23-0011 chassis and to the PSU module’s float-
ing ground contact.
The PSU module’s output is filtered by a ferrite sleeve on the positive line, and then
interfaces to the SL2 backplane via a Molex connector on the T800-23-0011 rear panel.
Additionally a ‘feed-through’ loom is connected to the Molex connector. This loom
forms part of the path for the programming and speaker connection between the SL2
backplane and the SL2 front panel. The external cable connection between the
T800-23-0011 and the SL2 backplane completes this path.
For the wiring diagram, refer to Section 6.2.1.