Nokia 9000i Service Manual page 264

RAE/RAK–1N
Faultfinding/Disassembly
First check the connection:
During startup the CPU (D130) enables the RS–buffer MAX3222 (D180)
by setting the RSENX (D180/pin1) low, RSSHDX (D180/pin20) high and
the IRSHD (M180/pin6) high. The signals RSENX and the RSSHDX are
toggled for the period of time that the CPU waits for a ping from the host,
typically 3.5s. Check if this happens and whether the signal levels are OK.
If the signals are OK, then proceed to 1.7.2. If the CPU does not control
the lines correctly, then proceed to 1.7.1.1
1.7.1.1 Valid Boot Code in UCS Flash?
If the boot code in the D163 is corrupted, then proceed to the 1 .1 If the
Flash is programmed, or it is sure that it contains valid data, and the CPU
doesn't control the RS–buffer correctly, then proceed to 1.7.1.3
1.7.1.2 Program UCS Flash
If there's no guarantee that the UCS Flash (D163) contains a valid boot
code, re–programme it with the JTAG method, or change to a good one.
After programming / replacing, return to 1.6
1.7.1.3 CPU, or UCS–Flash Fault
If the CPU (D130) doesn't control the RS–buffer although there is a valid
boot code in the UCS Flash (D163), then there is a fault either in the CPU,
or in the Flash itself. In most cases the fault is likely to be the CPU, but it
cannot be guaranteed unless the functionality of the UCS Flash is verified
with another system.
1.7.2 Activity in CPU RxD0 ?
If the RS–buffer is activated and the IR–tranceiver TFDS3000 (M180) is
put to active shutdown, then it's worth checking if the RSRXD line
(D130/pin114 –D180/pin10) is toggling, i.e. are the host's pings received
this far. If the line is toggling, and the signal levels are OK, then the CPU
receives the ping bytes.
If the RSRXD line is not toggling, but the input of the buffer RXD
(D180/pin9) is toggling, and the buffer control signals are OK, then
proceed to 1.7.2.1. If the RSRXD signal is toggling (in the CPU pin), then
the CPU should be transmitting acknowledgement bytes to the host. In the
case proceed to 1.7.3
1.7.2.1 RS–Buffer Fault
In the case that the signals seem to stop to the buffer (D130), although the
buffer control signals are set OK, then the buffer is likely to be defective.
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Technical Documentation
Original, 05/97