Sansui G 2000L Service Manual

Page 2

G VZOODSS/G VZOOOL

G-3000L

AM Section FM Section Others
«340005» (5000055, o-zoooL, G-SUOOL)
(SW1) Tuning range ..... as to 108 MHz Power rnoulremeirts

Tuning range . . . . . . .
Usable Sensitlvity . . .

23 to 6.5 MHx Usable sensitivity Power Voltage ..... 100, lZO, 220,20V
20 V Mono INF ....... 11.0 1131 .95 MV) (50/60 HX)¢-1ODOSS>

Selectivity [110 kHz) 45 on DIN . _ . , . 1.2 uv 210,24ov150 H1)
Signal to noise ratio . . . anon Stereo lHF ...... 19.0 oar
so on ouieting sensltlvity Power consumption , 155 watts (swz) Mono . 15 dB! 210 watts <5-3000L)
Tuning range . , . , . , . 6.5 to lle-lx Stereo 39 our Dimensions ........ 33 mm (17-1/l6)w
Usable sensitivity ..... 30 rrv Signal to noise ratio (at 65 oar) 153 mm (5-1/16") H
Selectivity (:10 kHz) as on Mono . . 71 on 352 mm SJ/8") 1:
Signal to noise ratio .. . 46d! stereo . . ex on Weight ...... . . 7.3 kg (16.I its) net
Distortion (at 5 nor) G-ZDOOSS, 2000L
49200, G»3WOL> Mono ......... less than 0.10% at loo Ht 3 kg (17.5 lbs) net
(MW) less than 0.15% at 1,000 H1 3.7 kg (19.2 lbs) packeo
Tuning range . , 530 to l,s00 kHz less than 0.25% at 5,000 H1 «3400055, G-2DOOL>
Usable sensitivity ar antenna) Stereo ......... less than 0.3% at 100 Hl 9.4 kg (20.7 lbs) packed
. . . . . . . . ..... 50 com (300 laV/m) less than 0.25% at 1,000 Hz
Selectivity (:10 kHz) 45 on less than 0.30% at 5,000 Hz
Signal to noise ratio . . . 46 on Alternate channel selectivity (at 400 Mix)
.......... 5000
(Lw) . . . 1.3 on
Tuning range ....... 150 to 350 kHz lmae response rzuo . 48 dB (at 98 MHz)
Usable sensitivity ..... 60 dBlln (1,000 ltv/m) Svurious "Spouse ratio . 70 dB (at 98 MHz)
(bar antenna) Stereo separation . . . . . 30dB at 100 Hz
300 W (5x1) 40 do at 1,000 in:
Selectivity ......... 45 as 23 dB at 10,000 Hz
5.3mm, "or...m , _ «.43 Frequency response . . . 30 to 15,000 Hz
+0.5 on -1.0 on
Antenna input impedance
............. 300 ohms balanced ~ Design and specifications subject to change without
75 ohms unbalanced notice for improvements.

1. OPERATIONS

Pop-noise preventive circuit

In order to prevent the annoying pop-noise 10 the loudspeakers
at turning the power of the amplifier ON, the pop-noise preventive
circuit adopted in the G-3000L is the combination of the con-
ventional driver-voltage delay type used in the power supply
(rectifier) circuit and the NF delay type pop-noise preventive cir~
cults. The configuration of NF delay type pop-noise preventive
circuit is shown in Fig. it

In this circuit, the switching (ON-OFF) of the transistor TROS is
made by the time constant ofthe capacitor C40 and resistor R88.
Thereby the NF resistor, R51 is controlled, and the gain of the
main amplifier stage is lowered when TROS is ON, thus the voltage
drift (transient voltage) of the main amplifier at turnng the
power ON does not appear on the speaker terminals for very short
period of time. in other words, at the instant that the power is
turned ON, the voltage at the point A rises up to +1 3V, then the
voltage decreases by means of the time constant of C40 and R88
as shown in Fig. 2. At this time, the diode DH is inversely biased,
consequently, the potential voltage of the point B is 0V as Fig. 3. £4me this point, the set begins
Because of this, TROS turns to the cut-off, thus the NF resistor, <-2 590°"d5-"-‚¬ woyking normally_

R51 acquires such a. start: as its resistance value becomes equiva~ rigzowergnage variation during a certain period

Iently very large, which decreases the gain of the power amplifier. or time at ®

When the charge of the C40 is completed, the voltage of the point
8 (see Fig. 3) becomes negative, as a result, the diode D1] is
biased. Therefore, TROS is turned 0N, and the circuit of this
equipment is normally operated approximately 2 seconds after
the power is turned ON to prevent the pop-noise which flows to
loudspeakers.

to speaker terminals

+13v

>
N
|

o

Time-9

VOLTAGE»

Time->

VOLTAGE->

0.72V

<- 2 seconds -~a-l,
.

Fig. 3 Voltage variation at ®