Power Supply (Sch. #0102-5037-03)

4.2.6

(Cont'd)

The functional operation of this unit is basic to the operation of the standard IC logic blocks used

throughout. The decade counters are connected with carry and reset lines to perform the standard

totalizer function. IC's 1Z1 through 6Z1 form the basic totalizer.

The display tube drivers take the outputs from the memory storage and provide the necessary voltage

gain to drive the display tubes. IC's 1Z3 through 6Z3 are the display tube drivers.

The memory storage is provided by a series of IC's that are updated only at the completion of the count

gate. The trailing edge of the count gate actually triggers the memory elements. Digits that have had no

change during the count gate remain unchanged and only -those that require changing are affected. IC's

1Z2 through 6Z2 are the memory elements.

A seventh storage IC, 7Z2, is used to store the overflow bit. The output of 7Z2 drives a transistor which

lights the O/F lamp.

The display tubes are driven directly from the output of the driver IC's 1Z3 through 6Z3. The display

tubes VI through V6 are glow-discharge numerical indicators that operate with a driving signal swing

(excursion) of approximately 50 V from the IC driver and require an excitation voltage of +180 V peak.

The conversion from binary to ten-line output is also supplied by the IC drivers.

Also on this board, as part of the O/F lamp assembly, is the GATE lamp. It is driven from a transistor

(Q7) on the logic board.

4.2.7

Power Supply (Sch. #0102-5037-03)

The Power Supply consists of a transformer, 4.5 V rectifier, filter and regulator and the +180 V rectifier

and regulator. Each supply is independent except that the +180 V supply uses the output of the +5 V

supply as its reference.

The +5 V supply uses a full wave center tapped rectifier, high capacitance filter C102 and a series

regulator. CR10 is the Zener reference element for the series regulator. R9 provides a means for

adjusting the supply to +5 V .05 V. This potentiometer is set at the factory and should not require

adjustment except after replacement of critical components within the power supply.

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