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Chapter 5---Electronics

5-34 Model 250 Service Manual

8. Reinstall the Convergence/Deflection PCB by lowering the right side in

first until it clears the electronic module edge, then lowering the left side

in.

NOTE:

It may be necessary to fit the top 2 fins of the heat sync over the

electronic module frame lip at the left to get enough clearance for the right

side to be installed. Carefully fit the board over the mounting screws and

slide the PCB into position. Tighten the screws and reconnect the

connectors.

5.8 Scan Reversal PCB

Scan Reversal PCB - Main Functions

Reverses of scan in both horizontal and vertical axes

Outputs deflection waveform to the Deflection Yokes on the CRTs

Outputs convergence data to Convergence Yokes on the CRT

Horizontal width adjustment for each color (R, G &B)

Scan failure detection for (horizontal and vertical) deflection amplifiers

Scan Reversal PCB - Inputs

H_OUT_FLYBACK - output horizontal deflection waveform from the Horizontal

Vertical Deflection PCB (about 800 Vpp).

H_LOCK (pos.) - horizontal interlock for the yoke connectors from the

Horizontal Vertical Deflection PCB (about 5 V when closed, 15 V when open).

H_RGB (pos.) - return of horizontal deflection waveform to the Horizontal

Vertical Deflection PCB.

V_RGB (pos.) - output signals of red, green, and blue from the Vertical Amplifier

of the Horizontal Vertical Deflection PCB (about 40 Vpp).

X_RGB (pos.) - output signals of the red, green, and blue from the Horizontal

Convergence Amplifier for the X-axis from the Convergence Deflection PCB.

Y_RGB (pos.) - output signals of the red, green, and blue from the Horizontal

Convergence Amplifier for the Y-axis from the Convergence Deflection PCB.

±15 V - input power from the Horizontal Vertical Deflection PCB for the analog

circuitry.

+5.1 V - input power from the Horizontal Vertical Deflection PCB for the digital

circuitry.

From Yokes

H_RGB_YOKE (neg.) - bottom of red, green, and blue horizontal deflection

yokes.

V_RGB_YOKE (neg.) - bottom of red, green, and blue vertical deflection yokes.

X_RGB_YOKE (neg.) - bottom of red, green, and blue x-axis convergence yokes.

JVC 250 User Manual

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