Nokia 9000i, Service Manual

Page: 281 / 434

After Sales
Technical Documentation
RAE/RAK–1N
Faultfinding/Disassembly
Page 8 – 39
Original, 05/97
7.3 Input a Byte via IR
If the sending of a byte was successful, try then to receive one. Choose
the Input mode in the service software, and choose a byte to be received.
7.4 Received Byte OK?
If the service software reports success, the IR test can be considered to
have been successful, otherwise proceed to 7.4.1
7.4.1 IRSHD, RSENX, RSSHDX OK?
When the 9000 begins to receive the byte, 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 7.4.1.1 If the signals are OK, then go to
7.4.2
7.4.1.1 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 7.4.1.2, otherwise go to 7.4.1.3
7.4.1.2 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 7.4.1
7.4.1.3 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.
7.4.2 RSRXD Activity?
If the byte is received by the IR tranceiver, then the RSRXD line toggles
right after the control signals are toggled. If the RSRXD signal toggles
proceed to 7.4.2.1, otherwise go to 7.4.2.2.
7.4.2.1 CPU Fault
If all the signal lines to the IR tranceiver toggle as they should, and there
is activity in the RSRXD while the IR transmitter connected to the host PC
is transmitting the byte, then the CPU is likely to be faulty.
7.4.2.2 M180 Fault
If the RSRXD signal does not toggle, then the M180 is likely to be faulty.