TCL TV [M113 Super One Chip Chassis] - Using TMP A8809 - M113 CPU] - Models 2500PF - 2501PF - 2506PF - 2900PF - 2901PF - 2905PF - 2906PF - 2907PF - SERVICE MODE
- After power on, press “volume ▼”on front panel waiting for the scale to“0”
- Then press key “DISPLAY” on the remote handset, there will be “D” displayed on the screen shows it enters in factory mode.
- Now the short-cut keys on the factory adjustment remote handset can be remark customer mode remote handset also can be used it can be used in repairing
- Adjustment press key “STANDBY” to exit factory mode but system setting data”6”should be kept the state before storing do not to change it.
Changed factory data and restored in memory.
- For factory production you can set “BIT-0”to“1”in menu “OPT”, so every time you press the remote handset can enter “D-MODE” directly after open the sets in AC or DC power sets on, also it can be activated by key “D-MODE” on the remote handset but do not forget to set“BIT-0”to“0”in menu “OPT” and power them on in AC or DC mode one time in the end of production so the sets will disable factory mode.
The key “I²C”on the remote handset can interrupt the communication CPU with I2C bus, usually this interrupt state can be used in automatic white balance adjustment and auto geometry distortion adjustment.
Vertical Output Section
TMPA8809 outputs vertical saw-tooth wave from pin 16.It come
to pin1 of TDA8172 with DC coupling, and is amplified by inner difference
amplifier. Pin7 of TDA8172 is the same phase input terminal. R302 and R303 are
DC offset resistances. C304 is a filter capacitor. In application to M113, pin7
of TDA8172 is fixed as the DC amplify ref terminal. The amplified saw
tooth-wave comes out from pin5 and make the deflect coil to generate the
deflect current. R304 and C305 filtrate the inductive interference from the
horizontal deflect coil. R310 and C309 are usedto eliminate spurious
oscillation generated by the deflect coil and distributed capacitance
resonance. C308, R309, C307 and accessory circuit are in charge of draw AC saw tooth
wave out at the deflect coil terminal connected with R303A, and feedback to the
input terminal of TDA8172 (pin1) to correct the linearity of horizontal scan.
C301 is a high frequency decoupling capacitor.
D301 and C302 make up of a voltage pump up circuit. TDA8172
output a vertical kickback impulse from pin6 to locate the OSD characters.
Horizontal Output And FBT Section
The processor outputs horizontal drive impulse from pin
13(H-OUT). The drive impulse is done with voltage division by R201 and R401,
and then comes to the base of the drive triode (Q401). C401 is used to eliminate
the noise in the H drive impulse. T401 is a horizontal drive transformer. Q411
is a horizontal output triode with a damper inside.L412 is connected with the
emitter of the horizontal output diode to eliminate the radiation and to
improve the distortions at the cross of vertical and horizontal white lines. C412
and C413 are retrace capacitors and C414 is an s-correct capacitor. L413 is
horizontal linear inductors. R441 is used to eliminate the parasitic
oscillation caused by horizontal linear inductors. C421, R421 and D421 are used
to correct the M-distortion in horizontal direction. The deflect coil and the
horizontal output triode have some resistance R while they are ducting. The resistance
R will cause the non-linear distortion, which means that the right direction
scanning speed of the electron beam becomes slower, and the right of the raster
is compressed to generate distortion. We use a horizontal linear adjuster to
compensate this kind of distortion. We use L414 as the H linear adjuster in horizontal
scanning section of M113 chassis. R419, which is parallel connected with L414,
is a despiking resistance for preventing the oscillation by compensating
inductor and the stray capacitance. The linear adjuster is a transductor coil
with a magnetic core inside. If the current, which pass the linear adjuster,
coil, increase to a certain value, the magnetic core becomes saturated to
decrease the inductance of the linear adjustment inductor. If the +B is steady,
the increase speed of Iy is faster to compensate the reducing of deflecting
current by the resistance R mention above. We can adjust the magnetic core to
change the inductance of the linear compensate inductor to adjust the H
linearity. The EW-correct signal sent frompin28 of TMPA8809, amplified
withQ412,Q413 and Q414,to adjust horizontal output circuit.
The EHT generation circuit
The FBT supply the anode high voltage, focus
voltage and screen voltage for M113 chassis. D441and C441 are in charge of
regulating the primary impulse of the transformer to output a voltage of 200V
for the video amplifiers. The ( 4 ) ~ ( 7 ) coils of the FBT supply the heater
with power. To limit the beam current in a safe range, we add a ABL(auto
brightness limit) circuit in M113 chassis. When the beam current is higher than
normal, Q451, which is an emitter follower strength conductivity, the emitter
gets a lower negative voltage, so the collector of it follows a lower voltage,
then gain of system brightness decreases, brightness decrease and beam current
decreases.
