FUNCTIONAL DESCRIPTION OF EQUIPMENT

TM 11-7025-217-30

b. Power Section. The power section consists of an input power filter assembly, POWER ON/OFF

circuit breaker, and an ac or dc power supply. The input power filter assembly attenuates conducted

radio frequency interference that may appear on the external power source. The POWER ON/OFF

circuit breaker protects the printer circuitry from overload and provides operator control of printer

operation. The power supply converts the input power to the +5V, +20V, -65V, -70V, and +80V

supplies required to operate the various printer circuits and components.

c. Logic Section. The logic section consists of control circuits, timing circuits, and data receive and

storage circuits. The control circuits permit manual and machine control of printer operations, The

timing circuits synchronize the printer functions, producing an ordered sequence of operations from

receipt of input data to printed output. Manual control is available to the operator by means of switches,

controls, and indicator located on the control panel at the front of the printer. The control panel contains

POWER ON/OFF circuit breaker, PAPER ADV switch, ILLUM control, SELF TEST switch, and FAULT

indicator light. PAPER ADV switch provides operator control of paper feed, and SELF TEST switch

provides the means of initiating self-test operation of the printer. The ILLUM control provides the means

of varying intensity of lamps used to illuminate the printed copy. The FAULT indicator lights when a

fault condition occurs in the printer. Machine control also prevents printing when no paper is present, or

when the door is open, or when there is a printhead short condition. The data receive and storage circuits

enable the logic to receive a maximum of an additional 33 characters while an ongoing print operation is

in process.

d. Print Section. The print section consists of the finger driver circuit card assemblies and print

system assembly which contain circuitry that converts data from standard digital logic levels to print-

head voltage levels that produce alphabetical characters, symbols, and numbers on electrosensitive paper.

The print section also provides motor drive and timing voltages required to properly feed paper through

the printhead mechanism.

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