Skanti TRP 5000, Instruction Manual

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5.9 Circuit Summary, AC Power Pack P5001
The circuit diagram is divided into a wiring diagram on page 8-109
showing the interconnections between the printed circuit boards of which
the Power Pack is composed, and circuit diagrams of the individual
circuit boards. The block diagram on page 8-63 illustrates the operation
of the Power Pack.
All necessary supply voltages for Transmitter Power Amplifier, Exciter
and Receiver are obtained through transformers T1 and T2. The
transformers give full isolation between the mains input voltage and
chassis, permitting these to be earthed without causing the mains leads
to be earthed.
Low tension voltages for Exciter and Receiver and negative grid voltage
for the Transmitter Power Amplifier are obtained through transformer T1
followed by rectifiers and stabilisers.
Transformer T1 also carries secondary windings for filament supply to
the P.A. valves and for the blower in the Transmitter Power Amplifier.
High tension for the Transmitter Power Amplifier is obtained through
transformer T2 followed by rectifiers.
Supply voltage for the driver stage in the Transmitter Power Amplifier
is also obtained from transformerT2followed by rectifiers and a voltage
stabiliser. Included in the Power Pack is also a loudspeaker connected
to the associated receiver AF-output.
5.11 Circuit Description, AC Power Pack P5001
5.10.1 /265\ TRANSFORMERS
A double mechanically operated safety switch is inserted in the mains
input leads. The primary current of transformer TI is controlled by the
POWER switch. Turning the switch from OFF to RECEIVE ONLY connects the
transformer to the mains and low tension is supplied to the Receiver.
Relay RL1 connects the primary windings of transformer T2 to the mains.
5.10.2 /266\ LT-STABILISERS
One output voltage from transformer 265 T1 is rectified in the chassis
mounted diodes 265 D1 and 265 D2. Two voltage stabilisers, one supplying
the Receiver and one the Exciter, have a nominal voltage of 7.5V.
Another output voltage from transformer 265 T1 is rectified in diodes D8
and D9 followed by a voltage stabiliser having a nominal output volta ge
of 15.7V. This voltage is supplied to both Receiver and Exciter.
The board also contains the keying relay RL2 f or the complete TRP5000
equipment. The contacts of the relay are used to disconnect the speaker
built into the Power Pack and to key the grid bias of the P.A. valves.