Nokia 9000i Service Manual page 280

RAE/RAK–1N
Faultfinding/Disassembly
7.1 Output a Byte via IR
Start the IR test from the service software. Select output mode and the
byte to send from the 9000. The external IR tranceiver should be
connected to the other serial port, where the DLR–1 cable is connected.
7.2 Sent Byte Received OK?
If the service software can receive the byte sent, continue to 7.3 otherwise
proceed to 7.2.1
7.2.1 IRSHD, RSENX, RSSHDX OK?
When the byte is sent, it toggles the RSENX from logic low to high,
RSSHDX at the same time from logic high to low, and after few
milliseconds the IRSHD from logic high to low. If these signals do not
toggle correctly, proceed to 7.2.1.1 If the signals are OK, then go to 7.2.2
7.2.1.1 M180 / pins 2,6,7 Disconnected?
To isolate a problem with the IRSHD, RSENX and the RSSHDX that does
not control the RS–buffer and the M180 IR tranceiver module correctly,
disconnect the control signals from the M180. If the pins are connected
continue to 7.2.1.2, otherwise go to 7.2.1.3
7.2.1.2 Disconnect M180 / pins 2,6,7
By doing this, the control signals can be isolated to the RS–buffer or to the
CPU. Go back to 7.2.1
7.2.1.3 RS–Buffer Fault
If the control signals do not toggle to the right state, even though the IR
tranceiver is isolated, then the fault is most likely in the RS–buffer (D180).
However it is possible, that the CPU does not control the lines. But since
the RS–buffer is needed for the communications to the host, it can not be
tested, if the control signals are disconnected between the CPU –
RS–buffer.
7.2.2 RSTXD Activity?
If the byte is already sent to the IR tranceiver, then the RSTXD line
toggles immediately after the control signals are toggled. If the RSTXD
signal toggles proceed to 7.2.2.1 otherwise go to 7.2.2.2
7.2.2.1 M180 Fault
If all the signal lines to the IR tranceiver toggle as they should, the M180 is
likely to be faulty.
7.2.2.2 CPU Fault
If the RSTXD signal does not toggle, then the CPU is likely to be faulty.
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Technical Documentation
Original, 05/97