SAMSUNG max800 Troubleshooting

Front PCB µ-com VDD(5V)

normal?

UIC1 pin no. 18,47,90

Replace RIC1

Main PCB RIC1(MC7812) : 12V

RIC2(MC7805) IN: 5V

Input voltage

normal?

Yes

Check the Power PCB;
RD2,3,4,5(1N5392)

Yes

Front PCB

Does UX1(12MHz)

oscillate ?

FRONT PCB PWR-SENS

voltage normal ?

(pin no. 27 ; 5V)

Check the Main PCB
RIC1(pin no. 10: 15V)

Yes

Front PCB

When the power is

ON 'H' displays

at pin no. 5 ?(5V)

Yes

Connect Front PCB and Main PCB.

Check the connector Main PCB.

Wafer MCW2

No

Replace µ-com.

Yes

No

No

No

No

Check the Power PCB : P/T, FUSE

No

Samsung Electronics 6-1

6. Troubleshooting

6-1 Amplifier

6-1-1 Power Malfunction

6-1-2 No Output

Yes

AQ1L,1R Base B+ ?

Is Mute selected ?

Headphone Jack short ?

Remove it with Remocon.

Replace Headphone jack
soldering condition.

Main PCB AIC1

(TDA7265)

pin no. 3

B+ circuits

Check the B+ power
source part in RD7,8,11,12
RC3 (38V)

Yes

Confirm for TR short
replace it.

Check if the output line is
short.

No

No

No

No

Yes

Yes

(AJ2)

6-2 Samsung Electronics

Troubleshooting

6-1-3 Tuner Malfunction(FM/AM)

IZD1(8.2V) Voltage ok ?

Yes

Check TUNER IC(LA1836)

pin no.10 ; 8.2V
pin no.14 ; 7.2V

AM ; 0V ?

Yes

LC72131

CONTROL ok?

Yes

FM VT

LC72131 pin no.20

1.7V 7.5V ?

Yes

AM VT

LC72131 pin 20

Check the LC72131

CONTROL ok?

Yes

Yes

Check HIC1

pin 20 ?

LPF1,2

output ok?

Check BIC1 TDA7439 function ok?

Check FEP interior

pattern, and any line

disconnections.

 1) Power impaired

so repair defects.

2) LC72131 Oscillator
(HX1 : 7.2MHz) ok ?

3) System line ok?

No

Yes

Check for µ-com IC

Replace LC72131

No

HZD1 (5.6V) Voltage ok?

HIC1 (LC72131) FM/AM BAND

Switching ok?

No

No

No

No

No

No

No

0.9V 7V

?

Power section defective

RIC1(MC7812) Voltage ok?

OUT: 12V

Check the voltage ok ?

No

No

Samsung Electronics 6-3

Troubleshooting