Genius 1493, ISO XFR-75W, 2093, 2793, 3693, 1793, 1993, ISO XFR-100W manual 200Ω

HORIZONTAL DEFLECTION CIRCUIT DESCRIPTION.

+24V to 27V Supply

2.2K.5W

1N4007

12-18VDC Hs

341

+

100uF

2SC4159E

33Vpp 27,E7

342

338

+12V Supply

3.92K

5.4-6VDC

3.92K

+24V

200Ω

2W

11, E5

337

340

GND

418

12

11

417

Remote

+ comp.

Control

PCB

Horizontal

1N4007

Horizontal

PICTURE

DELAYED

MULTIPLIER

POSITION

SYNC O/S

SAW TOOTH

Position

333

SYNC INPUT

O/S

TR . GENERATOR

BIAS

20K

RC7

0Ω

2

2.7K

8 1

2

3

4

5

6

484

RC4

202

I4

7

7.3-8.7V

Hs

7.3-8.7V

Vs

-.2VDC

Hs

3-4VDC

Hs

2.4-3.4VDC

4Vpp 02,D6

4Vpp

03,D6

1.5Vpp 04,E6

1.4Vpp 05,E6

0Vpp

06,E6

NEG.

56pF

12K

Hs

11

+

1.8K

I2

6.8K

1uF

3

IA

10K

7.3VDC

Hs

9

I13

347

I1

352

22K

8.8K

25K

330pF

18

I7

5.5Vpp 01,D6

45K

17

I3

I12

351

I5

350

348

+

1uF

I6

GND

6,10

GND

1

344

Horizontal

220uF

1,000pF-15KHz

0VDC

Hs

I PRA

6,800pF-15KHz

Sync

3,300pF-31KHz

330pF-31KHz

56Vpp 62,D6

416

3,300pF-38KHz

334

330pF-38KHz

The functions of the horizontal control circuits are:

1.To provide the horizontal output circuit with a stable frequency with or without incoming horizontal sync.

2.To be able to adjust the picture position, horizontally, with respect to the raster.

3.To operate stability through periods of missing horizontal sync pulses.

4.To keep the picture from drifting within the operating temperature range.

All of these functions except for the picture position adjustment are accomplished by the phase locked loop. Delaying the horizontal sync with an adjustable timer produces the picture position adjustment.

The horizontal sync input circuit (pin 1) will trigger the picture position one-shot (O/S) on either the rising edge, or the falling edge, of the horizontal sync pulse. To accomplish the edge triggering, the sync pulse is differentiated by capacitor 352 into two short pulses, one for the rising edge and one for the falling edge of the

sync pulse. Which edge is the trigger depends on the bias voltage at pin 1. For positive edge triggering, the bias voltage is set to 7.8 volts by

resistors	I2		and		I3	. For negative edge
triggering, the			bias voltage is set to 4.1V by
connecting				via the solder connection IA .
		I12

The picture position O/S clamps timing capacitor

351to 8.2 volts until horizontal sync triggers this O/S. The voltage on the timing capacitor drops at a rate set by the horizontal position control 484 and resistor

I4 . When the voltage, at pin 2, drops below 4 volts the delayed sync O/S is triggered and capacitor 351 is reset to its clamped voltage. The delayed sync O/S functions the same as the picture position O/S with the exception that it is not adjustable.

The flyback pulse, connected to pin 4 through

resistor I6 , starts the negative slope of the saw

tooth generator. When the sawtooth wave, which is

produced by a current to capacitor 348 , drops to 3

volts, the sawtooth generator switches back to the positive slope part of the wave till the next FBP.

During the active part of the delayed sync pulse, the multiplier gates current to capacitor 346 which is dependent on the sawtooth voltage at the delayed sync pulse time. Capacitor 347 sets the "0" voltage for the multiplier which is the average value of the sawtooth waveform.

If the delayed sync pulse occurs when the sawtooth is at a low voltage part of its cycle, capacitor 346 discharges and the oscillator frequency lowers. If the delayed sync pulse occurs at the top part of the sawtooth wave no current flows to capacitor 346 . This action, phase locks the horizontal oscillator to the incoming sync pulses.

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