Technics SA-X800L - Function of Terminal

AC EVM @ FUNCTION OF TERMINAL
© 1C203 (uPD1718G514) PLL controller
| PIN NO. | IN/OUT | MARK | DESCRIPTION OF TERMINAL
PLAYBACK GAIN ADJUSTMENT (DECK A/B)
1. Test equipment connection is shown in figure.
2. Playback test tage QZZCFM (315Hz)
3. Adjust VR301, 302 (DECK B) and VR303, 304 (DECK A)
for 410+10mV on AC Electronic Voltmeter (AC EVM).
(eno)
Segment signal output terminal for display.
o
({Lch) (Rech)
Common signal output terminal connected toLCD. Output is delivered in 3 vatues of
| ground, 1/2Vpp and Vpp (at 5ms intervals) in a period of 50 Hz.
The segment turns ON when the difference in voltage is + Vpp between these terminals and
LCD1~LCD23.
Power supply terminal of device. Voltage of 5V+10% is supplied during operation
of device.
To hold the internal date memory (RAM), the voltage can be decreased to 2.5V.
Note: Pins 7 and 33 are connected inside the chip. It is unnecessary to supply voltage to
the pins.
OUTPUT
e Adjustment Points
Not used in this unit.
Input is local oscillator output (VCO) in a range of 10~ 130 MHz (0.3 Vp-p, min.).
There are 1/2 fixed frequency division prescaler and 2-step (1/32, 1/33) prescaler internally.
Therefore, when deciding the frequency dividing value of programmable divider, it must be
decided from the frequency obtained by halving the local oscillator output (VCO).
Input is local oscillator output (VCO) in a range of 0.5~20 MHz (0.1Vp-p, min.).
When the mode is shifted to FM, the AM terminal voltage automatically becomes the supply
voltage of device.
GND Ground terminal.
¢ Tuner P.C.B. e Main P.C.B.
LW ANT
trimmer
MPX VCO adj.
VR305
DECK A REC
CURRENT adj.
(Reh)
DECK A REC
CURRENT adj.
DECK A PLAYBACK
oan adj. (C302 397 pe
ch)| VR303 |
DECK A PLAYBACK ) |p
GAIN adj. =
(Rch) KL [_vR307 ](L ch
ros} Erexor |
LW ANT coil (Lch)
MW ANT coil
E01 Not used in this unit.
When the divided oscillator frequency is higher than the standard frequency, H-level output
is delivered from these terminals.
When it is lower, L-level (0V) output is delivered. When they coincide, it results in floating.
The signal level should be high when the device is
—
=
é
FM MONO
DISTORTION coil
12 OUTPUT
Device selection signal input terminal.
operated, and low when not operated.
With this terminal shifted to low level, LCD (liquid crystal display) turns off and the memory
is held.
Not used in this unit.
OUTPUT
INPUT Connecting terminat for crystal oscillator. The crystal connected is 4.5MHz.
INPUT A3 (SD) Terminal to put in stop signal during auto tuning. The voltage is 5V with broadcast
received, and OV without broadcast received.
A2
This is the interrupt demand signal input terminal. The signal from the control input
INPUT | (REMOTE | terminal is put into this terminal, demanding for interruption, then the flow of program will
CONTROL)| be unconditionally shifted to the address No. 1.
OUTPUT ; A1 (FM) FM/AM output terminal. (FM — 5V, AM > OV)
OUTPUT ONG) Auto/mono changeover output terminal. (auto — OV, mono —> 5V)
5.2msec
INPUT ae 2 Input terminal for key return =
signal from external key matrix. ov
KEY 0 0.5msec
FM offset coil
FM ANT
trimmer
13 INPUT CE
NC
x1
X2
DOLBY NR
_Yen) ea
ei (GND) WA
(con )
VR301 |(Lch) ERASE
DECK
BPLAYBACK
CURRENT
-
GAIN
adj.
adj.
ae VR302 |(Rch)
DECK B PLAYBACK
GAIN adj.
17
BIAS OSC
Coil
20
Nh —_
[KEY MATRIX]
24 [Pm No. 25 | 26 | 27 | 28 29
21 | UP | Mw on ae ao
2 5.2msec 22 |DOWN| LW one ca .
5 PB3 ‘ 5V
OUTPUT ? Output terminal for key return CH7/ | GH3/
. mH 23 - FM 5 "1 MEMORY
28 PBO signal to external key matrix. ov L iL
O.5msec 24 = | MODE cae apr | =
Terminal for FM IF ceramic filter frequency
compensation. A pulse is generated when the voltage of
terminal 13 rises.
OUTPUT PC3
Output terminal for key return signal to let the stereo
OUTPUT
PC2
indicator
light
up.
OUTPUT PCO
7 2msec Ww
WwW
Muting signal is delivered during operation of FM/AM
(4V during muting)
~
Not used in this unit.
Muting signal output terminal.
oe selector switch and tuning switch.
ae ae —12—