ViewSonic E95 - Page 52

4.5.9 FOCUS
Horizontal parabolic wave form the IC901 pin7 (M52723ASP) Sync trigger by the pin17 of IC901.
1C901 pin7 is horizontal parabolic O/P to drive Q902, Q903 and Q904 via T405 pin7 coupling to FBT
pin13. Vertical parabolic waveform is taken from Q904 via T405 pin] to FBT pin13. IC901 pin6/pin15
can control IC901 pin7 amplitude/phase by IC301 pin32/pin31.
4.5.10 TILT
Tilt CKT is operated a current of different direction on rotation coil. The IC301 pin33 output 0~SV to
1C701 pin2 to control the volt amplitude and polarity on IC701, IC701 pin1 output via Q701 Q702 to drive
rotation coil.
4.6 VIDEO
4.6.1 VIDEO AMPLIFIER (1C601)
The video amplifier module is composed of three amplifiers for red, green, blue channel.
The video input signal is fed to the video preamplifier IC601 (M52743BSP) (pin2 blue, pin6 green,
pin 1 red) through AC coupling capacitor C603, C604, C658.
The clamping pulse comes from IC301 pin28 to IC601 pin19. The blanking pulse come from P602
pin9 (HBL) and P604 pin3(VBL) to IC601 pin27.
1C602 is an integrated high voltage CRT driver circuit designed to drive R.G.B channel of CRT
4.6.2 On Screen Display (OSD)(IC603)
1C603 (MTV021N-25) is a on screen display generator. PinS for H-sync input, pin10 for V-sync input.
The IC603 is controlled by IC301 via P604 ISCL, ISDA to IC603 pin7, pin8.
The on screen display signal is output from pin]2 (B), pin15(G), pin14(R), pin13(B)connected to
mixer circuit of IC601 pin, pini4, pin13, pin9.
4.6.3 Auto Beam Limit CKT (A. B. L. CKT)
When beam current over 870uA by VR401, the voltage build at base of Q601 will be less then 3.5V,
then the voltage of pin15 of IC601 will be pulled down accordingly to reduce the video preamplifier gain
output. ,
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