Technics SUV 98 Service Manual

Page 2

I SAFETY PRECAUTION (This safety precaution" ls applied only in U.S.A.)

. Before servicing, unplug the power cord to prevent an electric shock.

. When replacing parts, use only manufacturers recommended components for safety.

. Check the condition of the power cord. Replace if wear or damage is evident.

. After servicing, be sure to restore the lead dress, insulation barriers, insulation papers, shields, etc.

. Before returning the serviced equipment to the customer, be sure to make the following insulation resistance test to
prevent the customer from being exposed to a shock hazard.

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o INSULATION RESISTANCE TEST

1. Unplug the power cord and short the two prongs of the plug with a jumper wire.

2. Turn on the power switch.

3. Measure the resistance value with ohmmeter between the jumpered AC plug and each exposed metal cabinet part. such as
screwheads antenna, control shafts, handle brackets, etc. Equipment with antenna terminals should read between 3M9
and 5.2Mfl to all exposed parts. (Fig. A) Equipment without antenna terminals should read approximately infinity to
all exposed parts, (Fig. B)

{ Note: Some exposed parts may be isolated from the chassis by design. These will read infinity.

Antenna
; terminal \3 f
z i
:
i' .
l Exposed 5 Exposed /
i metal metal
3 part part
I Ohmmeter Ohmmeter -v:-"
(Fig.A) (Fig. B)
i

l Resistance = 3M9 -5.2 M9 Resistance = Approx 00

, 4. if the measurement is outside the specified limits, there is a possibility of a shock hazard. The equipment should be
i repaired and rechecked before it is returned to the customer.

I I BEFORE REPAIR

(1) Turn off the power supply. Using a 100, 10W resistor, connect both ends of power supply capcitors(C703, 0704) in order
to discharge the voltage.

(2) Before 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 120V, 60Hz in NO SIGNAL mode is 250mA~500mA.

l PROTECTION CIRCUITRY

The protection circuitry may have operated if either of the following conditions is noticed:
* No sound is heard when the power is switched ON.
* Sound stops during a performance.
The function of this circuitry is to prevent circuitry damage if, for example, the positive and negative speaker
connection wires are shorted , or if speaker systems with an impedance less than the indicated rated
impedance of this unit are used.
if this occurs. follow the procedure outlined below:

1.Switch OFF the power.

2.0etermine the cause oi the problem and correct it.

3.Switch ON the power once again.
Note: ~ -.
When the protection circuitry functions, the unit will not operate unless the power is first switched OFF and then
ON again.