Alignments And Adjustments - Sansui 771 Service Manual

4. ALIGNMENTS AND ADJUSTMENTS
Abbreviation
Equipment Others
AM FM Generator Oscilloscope...........- Genescope ClOCKWISE bcceeedcoudscrewatersareus sees CW.
AM Standard Signal Generator ............ AM SSG Counterclockwise...... e d e Brenda ta nceier grate CCW.
FM Standard Signal Generator ............ FM SSG AMMA? ere Pow eed awe ncttale ch Ree aha ks ANT.
FM Stereo Generator...........eec cence eee Stereo SG MOO NATO e s sa eticxTas os pends knedae de Xs MOD.
OstillOscOpe: sextet sess ee hdaee veankeyess Scope
Audio Oscillator >< svscxyndoxsetiswees eats Audio Osci.
Distortions Meter wiiecsusateseawe Sean ies Dist. Meter
4-1. Driver Circuit Board Adjustment (See Figs. 4-1, 4-2 and 4-3)
Note: 1. Master Volume......... eee eeeeee Minimum
2. Speaker Selector ..........eeeees SYSTEM (A)
3. Make the SP terminals free (no load).
4. Confirm the AC Power Supply voltage.
5. After adjustment, run the unit for more than 5 minutes, then check and readjust necessary.
6 . Room temperature should be 18~28° (65~83°F) for bias current adjustment.
STEP SUBJECT EQUIPMENT MEASURE OUTPUT | ADJUST | ADJUST FOR CONDITION
1
DC OV L-ch DC volt meter
Speaker terminal F-1499
| OV +10mV
oStep down meter's range
L-ch VRO1 accordingly
(Fig. 4-7) o Change lead's polarity if
meter swings backward
2 DC OV R-ch Same as above Speaker terminal F-41499 Same as above Same as above
R-c VRO2
(Fig. 4-1)
3 Bias current
DC milliammeter F-1500
F-1499 19+1mMA
oStep down meter's range
L-ch FO1 VRO3 accordingly
(Fig. 4-2)
4 | Bias current Same as above F-1500 F-1499 Same as above Same as above
i R-ch FO2 VRO4
(Fig. 4-2)
Fig. 4-1 Fig. 4-2
milliam-
volt meter meter ©
mitliam-
meter
TLLLD PDO PLL
yf
ON LO
VRo2 VRo4
bias current DC OV DC OV bias current
volume volume volume volume