Technics SAEX 500 Service Manual

Page 2

SA-EX500

information by anyone else could result in serious injury or death.

[It WARNING

This service information is designed for experienced repair technicians only and is not designed for use by the general public. It does not contain
warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product. Products powered by electricity should
be serviced or repaired only by experienced professional technicians. Any attempt to service or repair the product or products dealt with in this service

I AM Tuner Section
Frequency range
MW 522 - 161 1 kHz (9kHz steps)
530 - 1620kHz (1 OkHz steps)
LW 144 - 288kHZ
Sensitivty
MW 20pV, 330pV/m
LW 45w
Selectivity
MW (at 999kHz) 55dB
LW (at 252kHz) 55dB
Image rejection
MW (at 999kHz) 40dB
LW (at 252kHz) 40dB
IF rejection
MW (at 999kHz) 55dB
LW (at 252kHz) 55113
I Contents
PAGE
0 PROTECTION CIRCUITRY ......................................................... 2
~ BEFORE REPAIR AND ADJUSTMENT ...................................... 2
° CAUTION FOR AC MAINS LEAD ............................................... 3

- OPERATION CHECKS AND MAIN COMPONENT REPLACEMENT 4 ~ 8
. FAN MOTOR TROUBLESHOOTING
- TROUBLESHOOTING
0 BLOCK DIAGRAM ...... ..
- TERMINAL FUNCTIONS OF ICs .............................................. 18

I Protection Circuitry

The protection circuitry may have operated it either of the follow-
ing conditions are noticed:

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

0 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 ifspeaker systems with an impedance less than
the indicated rated impedance of the amplifier are used.

I Before Repair and Adjustment

I Video Section

Output voltage at 1 V input (unbalanced) 1:0.1 Vp-p
Maximum input voltage 1.5 Vp-p
Input/output impedance 75 Q (unbalanced)
I General

Power consumption 230W

Power supply AC 230 - 240V, 50Hz
Dimensions (W x H x D) 430 x 136 x 358 mm
Weight 9.3 kg

Notes :

1. Specifications are subject to change without notice.
Weight and dimensions are approximate.

2. Total harmonic distortion is measured by the digital spectrum
analyzer.

PAGE
- TERMINAL GUIDE OF le, TRANSISTORS & DIODES..18 & 19
' SCHEMATIC DIAGRAM ..... .19 ~ 34
- PRINTED CIRCUIT BOARD . 35 ~ 42
' WIRE CONNECTION DIAGRAM ..... 43

- CABINET PARTS LOCATION... 44
- REPLACEMENT PARTS LIST .45 ~ 47
. RESISTORS & CAPACITORS. .47 ~ 51
' PACKAGING ............................................................................. 52

If this occurs, follow the procedure outlines below:
1. Turn off the power.
2. Determine the cause of the problem and correct it.
3. Turn on the power once again after one minute.

Note:
When the protection circuitry functions, the unit will not operate
unless the power is first turned off and then on again.

Disconnect AC power, discharge 4 Power Supply Capacitors C703, C704, C705 and 0706 through a 109 , 5W resistor to ground.
DO NOT SHORT-CIRCUIT DIRECTLY (with a screwdriver blade, for instance), as this may destroy solid state devices.
After repairs are completed, restore power gradually using a variac, to avoid overcurrent.

Current consumption at AC 230 V, 50Hz in NO SIGNAL mode should be 120 ~ 350 mA.

Current consumption at AC 240 V, 50Hz in NO SIGNAL mode should be 130 ~ 380 mA.

Page 10

SA-EX5OO

I Troubleshooting

This unit has test points on each circuit board block for use in troubleshooting.

CONNECTION

Connect either a CD player, tape deck or AF oscillator to the input terminals of the unit.

Connection Input Terminals
equipment of the unit

REQUIRED ITEMS

1. Testing with a CD player

Test disc (SZZP1054C / first progarm, lkHz, OdB)
2. Testing with a tape deck Test tape (QZZCLA / 315Hz, OdB)

3. Testing with a AF oscillator Set the output at 500Hz, 200mV

4. Oscilloscope (min. 10MH2) ----------- To measure the output waveform at the test points.

| TEST PROCEDURE FOR AMPLIFIER CIRCUIT |

When the CD player AF oscillator is connected: When the tape deck is connected:
Power on the unit. Power on the unit.
Set the input selector button of the unit to the "CD" postion. Set the input selector button of the unit to the "TAPE MONITOR
Set the Speaker ONIOFF button of the unit to the SPEAKERS postion.
"ON" position. Set the Speaker ONIOFF button of the unit to the SPEAKERS
"ON" position.

I Run the CD player I or I Run the AF oscillator I I:i_;l
Run the tape deck

(SZZP10540 / first program Oscillator output
lkHZ, 0:13 at 500Hz, 200mV QZZCLA
31 5H1, OdB
Using the Oscilloscope, check the output waveforms at the test Note: Connect the '+' probe of
points on the circuit boards of the unit in the following order: the oscilloscope to each
(L1,FI1)->(L2,R2)»(L3,R3)->(L4,R4)»(L5,R5)->(L6,Ft6). test point and the '-'
Refer to page 10. probe to chassis ground.
I TEST POINTS POSITIONS OF AMPLIFIEFI CIRCUIT I
k_I k_J

U
H516
tam L4
i=| / |=i |=I =|
_]'I C511 1'! J

L6 .1323
R6 J321

R5L5
N a. 0100301004
.11. M
I I L2 R2

L1 33;
._
R Jaoz

Page 44

SA-EX500

I Cabinet Parts Location

Fan motor assy

L ......... i

/%an motor assy

_44_