Table of Contents
Advertisement
C414, C415 and C427 are the capacitors for line return stroke, C406 is the line S correction capacitor,
and L402 is the linear inductance for line. E-W geometric correction signals are sent out by the (20)
of N201 and fed into the (12) of N301, which, after being rectified, will be sent out from the (11) of
N301 and, after being amplified by a triode V401(KSA614Y) and waveshaped by C403 and L401, put
into line scanning circuit for a geometric correction in transmeridional direction.
Both VD404A and VD404B are modulating damper diodes, and T444 is a line output transformer. VD202,
R275, R276, R259 and C256 constitute a HV tracking circuit to compensate HV variation caused by
variation of luminance, hence an automatic correction of change of picture geometric sizes along with
HV variation. R419, R249, VD201, R248 and C250 constitute a beam limit circuit.
Line return stroke pulses sent out by the (9) and (8) of line output transformer T444 will be rectified
and filtered to produce DC voltage +16.5V and +46V, which are then fed into the (4) and (8) of
N301for supply power to the forward and return strokes of field output integrated circuit, , and, the
voltage+16.5V will then be regulated by N401 KA7812A to obtain a DC voltage +12V for power
supply to such dwarf signal processing circuits as HF tuner TU101 TECC7949 , sound surface filter
SF101 K6264K and pre-IF amplifier N101 M9911A .
(7) sends out a heater voltage of 6.3Vrms ; (1) provides line sync signal to N201 TDA9373 ; and the
line return stroke pulse sent out by the (5) is rectified and filtered to obtain a DC voltage +180V for
power supply to video amplification circuit.
2.9 Analysis of video amplification circuit
Video amplification circuit is comprised of an integrated circuit N501 TDA6107Q and peripheral
components. R, G and B signals coming from the (51), (52) and (53) of N201(TDA9373)are sent to the
(2), (3) and (1) of N501 respectively. TDA6107Q , an integrated video amplification output circuit ,
contains three independent video amplifiers which amplify the input R, G and B, three basic color
signals, which are fed into the cathode of picture tube by (7), (8) and (9).
The (5) of N501 checks the dark balance output, and the check result thus obtained will be sent to
the (50) of N201 for adjusting the dark balance of picture. White balance will be adjusted by sending
out R, G and B, three basic color signals, under the control of I
and VD501 ERC24-06 constitute a luminous spot killing circuit of cut-off type.
Table 7 lists the pin functions and test data of TDA6170Q as the reference for maintenance. The data
is to be tested under the mode of 49.75MHz PAL B/G and cylindrical color card, using a model
FLUKE 79
instrument.
Table 7
Pin
Function
1
B input
2
R input
2
C bus. C504 4.7u , R504 10M
Resistance to Ground R
Working
Forward Test Back
Voltage V
2.9
7.6K
2.8
7.6K
38
Circuit Explanation
Test
7.4K
7.5K
Advertisement
Table of Contents
