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[未归类] because there is no sync signal input [复制链接]

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发表于 2010-8-18 14:34:25 |显示全部楼层
Introduction: At present,also rotating, many new color displays are used TLS1233N tail circuit integrated block form. I display board according to PARCO in kind, drawing in Figure 1 circuit diagram for the maintenance personnel for reference. TLS1233N TEXAS United States in 1995, the company's new 20-pin set of the three primary colors, as the place ...
Keywords: computer circuit
present, many new tail color display integrated circuits are used TLS1233N block form. I display board according to PARCO in kind, drawing in Figure 1 circuit diagram for the maintenance personnel for reference.

TLS1233N TEXAS United States in 1995, the company's new three-color 20-pin video amplifier circuit, and the previous amplifier LMl203 compared to the three primary colors, not only in the-3dB frequency can reach 100MHz Department more suitable for high-resolution color display, and high integration make the circuit more compact.
Tls1233N internal circuit shown in Figure 2, pin functions and voltages shown in Table 1.

one works
by the host graphics card output R, G, B color signals sent through the signal transmission cable displays, and through the connector CN301 of ③ ⑤ ① foot tail circuit input to the CRT. The following example to introduce the R-channel circuit principle: CN301 ③ R pin input signal through C305, R305 coupled to the U301 (TLSl233N) ③ foot, by R-channel amplifier A1, A2 amplification, and then followed by the Q1 launch, the ⑩ R color signal pin output current limit by the R321, the added total fat, common base amplifier Q303 the b pole. R signal by Q303, Q302 were made, were based amplification, the C319, R350 coupling limit, the red gun sent to CRT (cathode), R304 is the resistor matching.
regulation U301's ⑩ ⑩ feet foot or adjustable external resistor VR301, vr303 resistance size, can change the amplifier A7, A4's gain, so as to achieve the purpose of adjusting light balance.
as U301 17-pin connected through fixed resistors R315 12V power supply, so bright red gun is balanced regulation shall prevail,http://jijia.org/bbs, other, A1, A4, A7 3 foot external amplifier is also affected by the contrast ⑩ circuit control. Therefore, changing the size of adjustable resistor VR302, can change the size of the contrast control voltage, thereby changing the A1, A4, A7 3 amplifier DC operating point, to control the purpose of contrast.
amplifier A2, A5, A8, respectively by the comparator A3, A6, A9's control,http://www1.xincad.com/forum, as the comparator A3, A6, A9's working or not, by 11 feet with or without clamp control of strobe pulse, even in the absence of machine case, because there is no sync signal input, not produce clamp pulse, so shooting with the devices Q1, Q2, 03 cut-off, displays no grating. The comparator A3, A6, A9 work depends on the Q1, Q2, Q3 to provide the feedback signal and reference signal clamp circuit, so the comparator A3, A6, A9 constitute the negative feedback circuit.
conditioning adjustable resistor VR304, VR305 and VR306 resistance size, can change the gun tube green, red and blue guns guns the size of the cathode voltage to achieve the purpose of adjusting the dark balance.
the video amplifier circuit to increase the dynamic gain, the tube gate (G1) plus negative pressure, to change the size of the negative pressure, can change the picture tube cathode emission electron beam number, which can change the screen brightness level of the background .
Figure 3 shows the ABL circuit. When the CRT beam current increases, the line output transformer ⑦ foot fall potential by R802, R735,http://wearethebestkai.1stfreehosting.com, after sampling, so that (1806 turn, lead to potential TLSl233N ⑩ foot drop down the amplifier gain, so CRT beam current is reduced; C810 is to prevent malfunction capacitance, R826 is the current limiting resistor.

2, Troubleshooting of
1. black
the main reason is to speed up very black (G2) voltage clamp pulse anomalies or (CLAMPGATE) Exception .
normal acceleration voltage is about 268V (1000V digital multimeter measured profile), if there is no line scan circuit voltage should be checked whether the work; if the voltage is low, check whether the resistance increase of R354, C332 is leakage. When accelerating voltage is normal, if ⑩ pin voltage 12V, shows no clamp pulse input; in the confirmation Q301, R312 normal, the point of failure on the motherboard.

[2. lack of color
lack of color because the corresponding amplifier is usually no work, no color letter
number corresponding input or CRT electron gun aging: no blue signal as an example below to enter
line analysis.
first place digital multimeter \diode, \failure
point in the video amplifier output circuit or tube: troubleshooting process shown in Figure 4.
3. brightness of dark circles as much for the contrast made virtual
video amplifier circuit or circuit abnormality; Trouble process as shown in Figure
5;
4. brightness lost control, there is loss of flyback lines
brightness control, a flyback lines, indicating tube-gate voltage difference is too low overcast. so
barrier maintenance process shown in Figure 6.
5. normal brightness, image made virtual
fault mostly CRT tube socket or focus voltage abnormality. open the tube seat tube
focus very lid inspection, if Focus voltage lead a green oxidation,
shows CRT tube socket moisture leakage; Otherwise, mostly line output transformer exception.
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RE: because there is no sync signal input [修改]
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