Toshiba TW40F80 manual Convergence Output Circuit

6. CONVERGENCE OUTPUT CIRCUIT

6-1. Outline

This circuit current-amplifies digital convergence correction signal at output circuit, and drives by convergence yoke to perform picture adjustment.

Digital convergence output signal 6ch adjustment is done.

(H-R/G/B) (V-R/G/B)

6-2. Circuit Description

6-2-1. Signal flow

Signal which is corrected by digital convergence, is output to P708 (V, H R/G/B);

is input to Q751 (V) R/G/B, and is output to P713, P714 and P715;

is input to Q752 (H) R/G/B, and is output to P713, P714 and P715.

6-2-2. Over current protection circuit

All currents of Power supply, -15V, +15V and +30V are de- tected to protect CONV-OUT IC from damage due to output short of CONV-OUT.

Current value: Normal ± 15V approx. 700mA

+30V approx. 200mA

Detecting curren ±15V approx. 1.8A or more

+30V approx. 700mA or more protecting operation

6-2-4. CONV-OUT mute

In power-on operation, transistors Q765 and Q766 are made turned ON, and –15V is applied to pin 3 of CONV-OUT IC. These cause mute operation on CONV-OUT.

6-2-5. Operation of IC

1) Q764 (TC74HC4050AP)

Sync signal which is input from P711 1 VD, 2 HD, is, through buffer, supplied to digital convergence P708.

2) 3-terminal source

Q754 (+5V) Q755 (+9V) Q756 (-9V)

Source for digital convergence

3) Q767 (TC4066BP)

P711 4 SDAM, 5 SCLM : microcomputer. Busline, through Q767, is input to Digital Convergence P709, and is controlled.

4) To adjust from outside of digital convergence :

Put adjusting jig into 6P socket of P720. Iscs turns from H to L, switch of Q767 is changed over. Then busline from mi- crocomputer is cut off.

P720 3 SCLU, 4 SDAU

Controlled by external adjusting jig.

6-2-3. Pump-up source

CONV-OUT IC Q752 (H)

Pin 10 (+15V/H, PV)

Pin 5 (+30V)

By HD input signal, pump-up is done only in horizontal re- tracing time.

	Pump-up
	Pump-up source waveform
Horizontal correction wafeform
+30V	+30V
+15V	+15V
	0V
0V	-15V
-15V
	Horizontal correction waveform

Fig. 11-13

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