3170-avs.ib.rev5.doc
page 5 of 16
16/10/2007
Technical description
The 3000 series of switchers and controllers share a common logic control system. For detailed information
regarding compatible switcher modules and control panels refer to the
3000 Series Switcher
manual.
Power supplies:
(See diagram 803142 sheet 2.)
Input power may be fed by a number of means.
1. One or two 14 - 0 - 14 Vac supplies via connections on the 64 pin DIN rear connector of the module. (Used
when module is mounted in FR-700 chassis or FR-748A chassis fitted with one or two PT-701 PSU’s.)
2. Two
±
16 Vdc supplies via connections on the 64 pin DIN rear connector of the module. (Used when module
is mounted in FR-748A chassis fitted with one or two PT-748A PSU’s.)
3. One 14 - 0 - 14 Vac supply and one
±
16 Vdc supply via connections on the 64 pin DIN rear connector of the
module. (Used when module is mounted in a FR-748A chassis fitted with 1 x PT-701 PSU and 1 x PT-748A
PSU.)
4. A single 14 - 0 - 14 Vac supply connected to the 3 pin male connector on the module side of the rear
assembly. (Used when module is mounted in FR-722 chassis.)
The input power is isolated by fusible resistors F 1 to F 4. Should these fail they should be only replaced by a
similar type of the same value or protection of the common power supply will be compromised.
If an AC supply is provided, the isolated AC is full wave rectified by diodes D 10 to D 13 and D 14 to D 17 to
provide a raw DC voltage of approximately 20 V at filter capacitors C 1 and C 13. The actual voltage will vary
depending on the type of frame, loading of PSU by other modules and the local mains supply voltage.
If a DC supply is provided, the isolated DC passes through the diodes D 10 to D 13 and D 14 to D 17, which
provide protection against accidental reverse polarity connection of the DC supply. Where a DC supply is used, the
input voltage must be at least
±
15 Vdc under all conditions to ensure sufficient margin for the proper operation of
the following voltage regulators and losses in the input fusible resistors and diodes.
The raw DC power is fed to three terminal regulator IC’s that provide
±
12 Vdc rails for the video circuits. The
+12 Vdc is also supplied to the remote logic connector PL 4 pin 1A via a current limiting resistor R 24 for use by
control panels.
The +12 Vdc rail is further connected to another three terminal regulator to provide the +5 Vdc required by the
logic control circuits.
A number of 10
µ
F tantalum tag capacitors are located at key points in the circuit to suppress interference on the
DC rails. Should any of these fail they should be replaced by high quality tantalum tag capacitors of at least 16 Vdc
rating.
A green LED on the front panel indicates presence of DC power in the module. This LED is supplied from the +5
Vdc regulated supply rail via R 23.
If the module is fitted with local control buttons (CPS-3050) or a local tally panel (TPS-3010) then LD 1 the DC
power indicator LED is omitted.