Technics SUX 901 Service Manual

Page 2

I CONTENTS

Page Page
BEFORE REPAIR ..................................... 2 PRINTED CIRCUIT BOARDS ........................ 23~26
PROTECTION CIRCUITRY 2 TERMINAL GUIDE OF ICS,
ACCESSORY ............. 2 TRANSISTORS AND DIODES . . . .
LOCATION OF CONTROLS . 3 WIRING CONNECTION DIAGRAM
CONNECTIONS 6 BLOCK DIAGRAM
DIGITALIZATION OF AUDIO SIGNALS 7 DESCRIPTION OF FL PANEL . . ..

DISASSEMBLY INSTRUCTIONS .........
MEASUREMENTS AND ADJUSTMENTS .
SCHEMATIC DIAGRAM ...................

FUNCTIONS OF IC TERMINALS
REPLACEMENT PARTS LIST
EXPLODED VIEW

I BEFORE REPAIR

(1)Turn off the power supply. Using a 100, SW resistor connect both ends of power supply
capacitors (C71 1, C712, 6800 uF) in order to discharge the voltage.

(2)Betore turning the power supply on , after completion of repair , slowly apply the primary voltage by using

a power supply voltage controller to make sure that the consumed current at 50Hz/60Hz in NO SIGNAL mode
should be shown below with respect to supply voltage 220V/240V.

Power supply voltage ACZZOV ACZ40V
Consumed current 50Hz 200~500 mA 180~450 mA
Consumed current 60H2 200~500 mA 180N450 mA

I PROTECTION CIRCUITRY

The protection circuitry may have operated it either of the lollowing conditions is noticed:

* No sound is heard when the power is switched ON.

* Sound stops during a performance.

The Iunction of this circuitry is to prevent circuitry damage it. for example, the positive and negative speaker
connection wires are shorted" , or it speaker systems with an impedance less than the indicated rated
impedance of this unit are used.

It this occurs, tollow the procedure outlined below:

1.Switch OFF the power.
2.Determine the cause of the problem and correct it.
3.Switch ON the power once again.

Note:

When the protection circuitrytunctions, the unit will not operate unless the power is first switched OFF and then
ON again.

I ACCESSORY

IAC power supply cord ....................................... 1
Configuration 0! AC power supply cord dilters according to
area.

SJA188 .......... For (EB) area only.
SFDA005E03 . . . .For others.