Technics SUV 470 Service Manual

Page 2

-V470

I CONTENTS

BEFORE REPAIR AND ADJUSTMENT
PROTECTION CIRCUITRY
ACCESSORY
LOCATION OF CONTROLS .........................
CONNECTIONS
DISASSEMBLY INSTRUCTIONS
SCHEMATIC DIAGRAM ............
WIRING CONNECTION DIAGRAM ........................

12

PRINTED CIRCUIT BOARDS
TERMINAL GUIDE OF IC'S.
TRANSISTORS AND DIODES ..................
BLOCK DIAGRAM
MEASUREMENTS AND ADJUSTMENTS
REPLACEMENT PARTS LIST
EXPLODED VIEW

I BEFORE REPAIR AND ADJUSTMENT

(1) Turn oil the power supply. Using a ton, 10W resistor, shortcircuit both ends oi power supply capacitors

(C705,C706)in order to discharge the voltage.
(2) Belore turning on the power switch of the unit.

A.

B.

Connect the voltage controller to the primary side.

ol the secondary side.

Connect the AC ampere meter to the primary side or connect the DC voltage meter to the 18" circuit

. Turn the WI at lCQ (VR451 and VR452) to minimum (counterclockwise).
. After setting the output to zero of the voltage contoller,turn on the power switch of the unit.

And increase the output at voltage controller gradually.

Then, check carelully whether the current value at primary side become more than iollowing value or

whether the DC voltage ol secondary side is increasing slowly.

level of voltage contoller Immediately.

voltage of the unit.)

. it the value at current Is Increasing unusually or the DC voltage is not increasinglower the output

The current value at the primary side at no signal. (Confirm the power supply voltage oi each area and provided

Power supply voltage AC 220 V Ac 240 V
Consumed current 50 Hz 60~240 mA 55~220 mA
60 Hz 56~227 mA 52~208 mA

I PROTECTION CIRCUITRY

The protection circuitry oi the amplifier may have

operated it either 0! the iollowing conditions is noticed:

o No sound is heard when the power is turned on.

0 Sound stops during a perlormance.

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

at the amplilier are used

I ACCESSORY

If this occurs. lollow the procedure outlined below:
1.Turn oil the power.

ZiDetermine the cause ol the problem and correct it.
3.Turn on the power once again.

Note:

When the protection circuitry lunctions. the unit will not
operate unless the power is lirst turned oft and then

on again.

oAC power supply cord .
(SFDACOSEOS) . For [E] and [EG] areas.
(SJA193) ............ For [EB] area only.