Nokia 9000i - Troubleshooting Diagram of the RS-232 Check

After Sales
Technical Documentation
RAE/RAK–1N
Faultfinding/Disassembly
Page 8 – 40
Original, 05/97
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.
1.
Test COM1 in local
loop
3.
Test COM2 in local
loop
5.
Connect
RBUSRXD and
RBUSTXD together
0.
Start
2
.
Test
NO
successful?
YES
NO
4.
7.1
Test
NO YES
successful?
R974
OK?
YES NO
7.
Test YES RS–232 Check
successful? OK!
2.1
CPU fail
6.
Test COM2 in
external loop
7.1.1
Change resistor
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