Sony st s 555 es service manual

Page 2

ST-5555ES

FM tuner section

Tuning range
Antenna terminals

875 MHz » 108 MHZ
two, 75 ohms, unbalanced

Intermediate frequency

10.7 MHZ

at 40 kHz deviation at 75 kHz deviation

Sensitivrty

at 46 dB quieting
2 av (mono)
22.5 )iV (stereo)

at 50 dB quieting
16.8 dBt, 1.8 W (mono)
37.9 dEt, 22.5 V

(stereo)
Usable sensitivity 0.8 uV (SIN : 26 dB) 10.3 dBf, 0.9 uV (IHF)
Signal-to-noise ratio 86 dB (mono) 92 dB (mono)

80 dB (stereo) 86 dB (stereo)

Harmonic distortion

IF BAND I WIDE
0.03% (mono) 0.05% (stereo) at 100 Hz
003% (mono), 0.04% (stereo) at 1 kHz
003% (mono), 0.12% (stereo) at 10 kHz
IF BAND ' NARROW
0.05% (mono), 0.07% (stereo) at 100 Hz
0.05% (mono). 0.06% (stereo) at 1 kHz
0.05% (mono), 0.15% (stereo) at 10 kHz

,7 i
Selectivity at 300 kHz at 400 kHz 7
30 dB 60 dB
(IF BAND: WIDE (IF BAND: WIDE)
57 dB 90 dB
(IF BAND: NARROW) (IF BAND : NARROW)
Capture ratio 1.0 dB
AM suppression ratio 65 dB
Image response ratio 120 dB
IF response ratio 100 dB
Spurious response ratio 120 (18
RF intermodulation 75 dB (IHF),

100 dB (24 MHZ)

Sub-carrier product ratio

Muting threshold
Auto-tuning threshold

78 dB
Approx. 25 dBt, 5 av

IM distortion IF BAND: WIDE
0.03% (mono), 0.04% (stereo)
Separation IF BAND: WIDE

55 dB at 100 Hz
60 dB at 1 kHz
45 dB at 10 kHZ

lt0Hz-12.5I 30Hzi15kHz :ggaa

[ Frequency response

_ 02
30H: 15kHz :05 dB

Approx. 25 est, 5 pV

Output level/impedance (75 kHz deviation)

750 mV, 620 ohms, transformed by the sup-
plied A.C.T, cable

Calibrating tone level

50% modulation (37.5 kHz deviation).
400 Hz

Antenna 8 attenuator 20 dB

SAFETY CHECK-OUT (US Model)

After correcting the original service problem,
perform the following safety check before releasing
the set to the customer:

Check the antenna terminals, metal trim, metallized
knobs, screws, and all other exposed metal parts for
AC leakage. Check leakage as described below.

LEAKAGE TEST

The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5 mA (500 microampers). Leakage
current can be measured by any one of three
methods

I. A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers instructions to use these instru»
ments.

to

A battery-operated AC miIIiammeter. The Data
Precision 245 digital multimeter is suitable for
this job,

Measuring the voltage drop across a raster by
means of a VOM or battery-operated AC volt-
meter. The limit" indication is 0.75 V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
suitable. (See Fig. A)

Fig. A. Using an AC voltmeter to check AC leakage.

To Exposed Metal
Part: on Set

0.15pF I 7.5kil

"T- Ea/m Ground

A C
voltmeter
(0. 75 VI