Technics Quartz ST-G7 User Manual

m@ CONTENTS
Page Page
SAFETY PRECAUTION .......... 000 ee eee eee 2 FUNCTION OF LIQUID CRYSTAL PANEL............ 16
FEATURES. core fe Scobie: Sa a heh ay eines WTA Eel a She BUA he 2 WAVEFORMS: 2.2555. cose gi 5 BG a ok Fhe eG wae ws Shei ts 17
LOCATION OF CONTROLS............0+ 00 eee 3,4 BLOCK DIAGRAM .......... 02 e eee eee 18,19
HOW TOOPERATE...........-02.-0 22 ee eeeee 4~6 CIRCUIT BOARDS AND WIRING CONNECTION
BEFORE REPAIR AND ADJUSTMENTS ............. 7 DIAGRAM 22. ieie 8 fee 8 es Ei ea ee 20 ~ 22
DISASSEMBLY INSTRUCTIONS ...............- 7~9 SCHEMATIC DIAGRAM ..........0 000 eee 23 ~ 28
HOW TO USE THE AMLOOP ANTENNA ............. 10 TERMINAL GUIDE OF TRANSISTORS, IC’S AND
MEASUREMENTS AND ADJUSTMENTS ......... 10 ~ 13 DIODES 5 i.e. 200 kee eS era eh ag te tera Bee aS 29, 30
FUNCTION OF TERMINAL (MPX IC301 -AN7471S)...... 14 RESISTORS AND CAPACITORS .............. 29 ~ 31
FUNCTION OF TERMINAL (PLL CONTROLLER IC902. REPLACEMENT PARTS LIST..............245 31~ 33
MIN 12919) cece seh a oe oS eee ww ee Sse st eb ees eS ete 14 EXPLODED VIEW... 1.2... ee tt te es 33, 34
FUNCTION OF TERMINAL (MICRO COMPUTOR !C903 -
MN1554STD)... 2.2... 2-0-0 eee ee 15
m@ SAFETY PRECAUTION
. Before servicing, unplug the power cord to prevent an electric shock.
. When replacing parts, use only manufacturer’s recommended components for safety.
. Check the condition of the power cord. Replace if wear or damage is evident.
After servicing, be sure to restore the lead dress, insulation barriers, insulation papers, shields, etc.
. Before returning the serviced equipment to the customer, be sure to make the following insulation resistance test to
prevent the customer from being exposed to a shock hazard.
ORWNH
e INSULATION RESISTANCE TEST
1. Unplug the power cord and short the two prongs of the plug with a jumper wire.
2. Turn on the power switch.
3. Measure the resistance value with onmmeter between the jumpered AC plug and each exposed metal cabinet part, such as
screwheads antenna, contro! shafts, handle brackets, etc. Equipment with antenna terminals should read between 3MQ2
and 5.2MQ to all exposed parts. (Fig. A) Equipment without antenna terminals should read approximately infinity to
all exposed parts. (Fig. B)
Note: Some exposed parts may be isolated from the chassis by design. These will read infinity.
Antenna
terminal
Exposed Exposed
metal metal
part part
Ohmmeter Ohmmeter
(Fig. A) (Fig. B)
Resistance = 3MQ2—5.2MQ Resistance = Approx oo
4. If the measurement is outside the specified limits, there is a possibility of a shock hazard. The equipment should be
repaired and rechecked before it is returned to the customer.
@ FEATURES
@ Newly developed LS! successfully incorporating both ®@ Self-computing RF tuning circuit capable of receiving
digital
(signal
control)
and
analog
(linear
&
signal
trans-
desired
station
under
the
best
conditions.
Mission) circuits in one body. @ FM-IF automatic IF band selecting function.
@ Extra-wide dynamic range of 116 dB (1 kHz), low dis- @ |nput/output terminal for personal computer con nection.
tortion of 0.01% {1 kHz), and stereo separation of @ Multi-function LCD intensive display.
65 dB (1 kHz). @ Reference signal 0.33 kHz record checking signa ! Output
@ Linear detector and linear demodulation digital detector
Circuits,
function,

Technics Quartz ST-G7 Specifications

General

Brand	Technics
Model	Quartz ST-G7
Category	Tuner
Language	English