group supplying power for 3.3V is lower, it adopts 17431. For two ICs are different, you should
pay special attention to distinguish them from each other. They cannot be used mixing.
Chapter 5: Panel control and VFD display circuit
The panel mainly consists of VFD screen, driver IC0793, remote receptor HS0038A2 and
button and indicator display circuit, mainly for accomplishing man-player dialogue and display of
operation status.
The structural drawing is as follows:
Figure XI
MT1389 will control the U401 IC 0793 to display the operation status of the player through the
VFDST status, VFDCK clock and VFDAT data, under the control of CPU built in MT1389,
receive the user control commands sent by UPD16312, and control the controlled circuit of the
player to limit the player to operate in specified status.
When the user operates the panel buttons, the control command is sent to the IC 0793 through
keyboard-scanning circuit, and through internal decoding drive, the IC 0793 outputs the control
data from the pins 5 and 6 (VFDAT) to the built- in CPU of MT1389, which will realize the control
on the controlled circuit, and control the VFD through IC 0793.
ＶＦＤ４０１ ｉｓ ａ ｖａｃｕｕｍ ｆｌｕｏｒｅｓｃｅｎｃｅ ｓｃｒｅｅｎ， ａｎｄ ｉｔｓ ｂｉｇｇｅｓｔ ｆｅａｔｕｒｅ ｉｓ ｉｔｓ ｈｉｇｈ ｂｒｉｇｈｔｎｅｓｓ．
Its operation principle is similar to the kinescope of TV. The pins 1, 2, 34 and 35 are for filament
power supply; the pins 27-32 are GRID poles, each GRID has 16 different characters of display;
the pins 4-19 are SEG poles, and the CPU control the SEG poles through its control on IC 0793,
and display the characters of corresponding operation status on the screen.
The remote reception circuit mainly consists of remote receptors HS0038A2, of which the pin 1 is
for grounding, the pin 2 for power supply, the pin 3 for output of reception signal, and they are all
connected directly to the CPU in MT1389 to control the corresponding circuit.
This player has headphone output function. A pin in the headphone directly connects to TAS5508. When the
headphone is inserted, detection line H-DET grounds and turns into low level. When pin 12 of TAS5508 turns
U401
IC 0793
VFD
displ
ay
Keystroke
control
U201
MT1389
Remote
receiving
Panel indicator control
VFDST
VFDCK
VFDAT
