Samsung MAX-485 - Troubleshooting

7. Troubleshooting
7-1. The Amplifier section
7-1-1. Power malfunction
Main PCB
MIC16
Input voltage normal?
FRONT PCB
u-com VDD(5V) normal?
FIC1 #13,47,90
Replace MIC 16
FRONT PCB
Does FCF1(12MHz)
. itoscillate? _~
ra
FRONT PCB
PSNS voltage normal?
(#28)
FRONT PCB
When the power is
ON, ‘H' displays
at no.9? (5V)
X
—_> Replace MICOM
Check the power
circuit, MC24(3N246),MC71
Check; FRONT PCB
FD7,FC16,FR44,FZD1
PSNS circuit
High
displays?
Wafer5
At the base of x Connect FRONT PCB and MAIN PCB.
MAIN PCB,MTR12(C945) Check the connector Main PCB
MTR12 and
the Collector
becomes 'Low'?
Replace MTR12
Check the power switch
Circuit of MTR10, MTR9
oy —