Mitsubishi Electric Diamond Pro 930SB, Руководство по обслуживанию

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7-6
5. Horizontal Deflection
a) U501 is a horizontal signal processing IC. Horizontal Driver signal is output from pin 8 of U501 TDA4856
and through Q506, Q507 to drive Q313 and T304.
b) T304 is an on/off type driver transformer. It functions to convert primary energy to secondary, and drive
the horizontal output transistor Q314.
c) Horizontal linearity compensation circuit:
1) The main component is that T303 is Linearity coil and Q325, Q326 is amplified.
2) The control voltage is from U701 PIN 31.
3) C362 is the Cs capacitor, and Q315 controls C334, Q317 controls C336, Q319 controls C338, Q321
controls C340, Q323 controls C341. The U701 pin 11, 16, 17, 18, 19 controls the Q315, Q317, Q319,
Q323 and Q321 respectively. So different frequency has different combination to meet the requirement.
No Signal fH(kHz) fH CS3 CS0 CS4 CS2 CS1
HL DAC(%)
H.LINEAR
1,3 VGA350/400/480 31.469 31k < < 34K 1 0 0 0 1 30.1
4 640*480(Mac13) 35 34k < < 36.5k 1 0 0 1 1 50
17 640*480(75) 37.5 36.5k < < 40k 0 0 1 1 1 30.1
2 640*480(85) 43.269 40k < < 44k 0 0 0 0 30.1
5 800*600(75) 46.875 44k < < 49k 0 1 0 0 0 50.1
7 832*624(Mac16) 49.725 49k < < 52k 0 0 1 0 0 30
6 800*600(85) 53.674 52k < < 58k 0 1 1 0 0 50
8 1024*768(75) 60.023 58k < < 62.5k 0 0 0 0 0 50
62.5k < < 67k 1 0 0 1 0
9 1024*768(85) 68.677 0 1 0 1 0 25
10 1152*870(Mac21) 68.681
67k < < 74k
0 1 0 1 0 25
11 1280*1024(75) 79.976 74k < < 83k 0 0 1 1 0 35.2
16 1920*1440(60) 90 0 1 1 1 0 25
12 1280*1024(85) 91.146 0 1 1 1 0 25
13 1600*1200(75) 93.75
83k < < 98k
0 1 1 1 0 25
14 1600*1200(85) 106.25 1 1 1 1 0 25
15 1792*1344(75) 106.27
98k < < 110k
1 1 1 1 0 25
6. High Voltage & FBT Secondary
a) High voltage control circuit synchronize horizontal deflection pulse. U301 control and stabilize high voltage
by detecting high voltage via VR301. The polarity of Q306 OUTPUT is reverse of Q305 output.
b) Focus and screen voltage are come from FBT bleeder.
c) G1 bias is controlled through R323, R390, R324, Q307 and ZD303.
d) Q307 is controlled by MCU pin 2 Mute 1, and it will blank the picture during mode change.
e) Q401 is the blanking buffer to G1 to blank the retrace line of picture.
f) X-ray protection circuit has two ways. One is detected by using U501, the other is detected by U701 MCU.
R511, R532, R533 and C502 are the x-ray protection circuit. Once the HV rises abnormally, U501 win shut
down itself, all the horizontal deflection is stopped by then. R357, R358 also x-ray protection circuit. Once
the HV abnormally, MCU do shut down it self through U701 3 pin.
g) R301, C354, R352, Q309 and R318 are the overcurrent protection circuit, once the FBT over current,
U501 is shut down.