Troubleshooting Diagram Of The Rs-232 Check - Nokia 9000i Service Manual

RAE/RAK–1N
Faultfinding/Disassembly
8 Troubleshooting Diagram of the RS–232 Check
The following picture illustrates the serial port tests. As the COM1 is being
tested automatically in the communications to the host PC, only the COM2
can be tested externally with the aid of the service software. Both serial
ports can be tested in the UART's local loop.
0.
Start
1.
Test COM1 in local
loop
.
2
Test
successful?
YES
3.
Test COM2 in local
loop
4.
Test
successful?
YES
5.
Connect
RBUSRXD and
RBUSTXD together
8.1 Test COM1 in Local Loop
Choose the serial test in the service software and select COM1 to be
tested in a local loop. The test is ran at the same baud rate that is used in
the communications to the host PC.
8.2 Test Successful?
If the test passes successfully proceed to 8.3, otherwise branch to 8.2.1
Page 8 – 40
NO
NO 2.1 YES
CPU fail
6.
Test COM2 in
external loop
Technical Documentation
7.1.1
Change resistor
NO
7.1
R974
OK?
NO
7.
Test YES
successful?
After Sales
RS–232 Check
OK!
Original, 05/97