Troubleshooting - Samsung MAX-805 Service Manual

6. Troubleshooting

6-1 Amplifier
6-1-1 Power Malfunction
Front PCB µ-com VDD(5V)
normal?
UIC1 pin no. 18,47,90
Front PCB
Does UX1(12MHz)
oscillate ?
Front PCB
When the power is
ON 'H' displays
at pin no. 5 ?(5V)
Connect Front PCB and Main PCB.
Check the connector Main PCB.
Wafer MCW2
Samsung Electronics
No
Yes
No
Yes
No
Yes
No
Main PCB RIC1(MC7812) : 12V
RIC2(MC7805) IN: 5V
Input voltage
normal?
Yes
Replace RIC1
FRONT PCB PWR-SENS
voltage normal ?
(pin no. 27 ; 5V)
Yes
Replace µ-com.
Check the Power PCB : P/T, FUSE
No
Check the Power PCB;
RD2,3,4,5(1N5392)
No
Check the Main PCB
RIC1(pin no. 10: 15V)
6-1