Troubleshooting - Samsung MM-28 Service Manual

6. Troubleshooting

6-1 Amplifier
6-1-1 Power Malfunction
Front PCB µ-com VDD(5V)
normal?
UIC1 pin no. 90,97
Yes
Front PCB
Does UX1(12MHz)
oscillate ?
Yes
Front PCB
When the power is
ON 'H' displays
at pin no. 47 ?(5V)
Yes
Connect Front PCB and Main PCB.
Check the connector Main PCB.
Wafer JCW2,UCW1
Samsung Electronics
No
Main PCB RIC1(BA3950) IN: 38V
Input voltage normal?
Replace RIC1
No
FRONT PCB POSNS
voltage normal ?
(pin no. 27 ;5.0V)
No
Replace µ-com
No
Yes
No
Yes
Check the Power PCB;
RF1 (T3.15 AL 250V)
Check the Main PCB
RD5,RZD2,RR2,3,4,
RC4
6-1