NPM and NIS Both on fault
On our Site I have a Bailey INFI90 Line,There total number of CPUs are 7. One Node is disturbing after 3 or 4 days its NPM and NIS card goes to fault BUT MFP working normally so connection to Server drop. I note down the LED status of NPM and NIS. NPM led 2 and 5 showing red, all other off and NIS all led showing RED. So i take out the NPM card and re insert it then it working normal. as per manual NPM led status shows that it is handshake failure with NIS. so i change NPM with new card with same setting and also change the NIS card But after few days it again comes with same led status. What i do next
As you point out, the NPM is halting on a loss of communications with the NIS (NIS handshake failure) and as you have replaced both of the modules and there has been no improvement what about something external to the modules themselves such as...
a.) What's new or changed? Assuming that the problem hasn't been there for the last 20 years or so, has anything changed in or around the PCU that coincides with the problem occurring? A new or replaced UPS or power system or recently added IO fo example. "Correlation doesn’t imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing ‘look over there.’" - Randall Monroe
b.) System power. Check your DC voltages and confirm they are within spec for the power system you have installed. Not sure what version NIS/NPM you are running but the INNIS01/11 are sensitive to poor -15V supplies and/or imbalanced +/-15V supply voltages. This can either be the voltages themselves or through high frequency noise from the power supplies.
c.) Expander bus. Check for the expander bus segment being longer than it needs to be (2 slots) and if it is, are there are any other modules plugged in on the expander bus segment besides the NIS and NPM.
d.) NKLS01 cable is correctly installed. Check for broken latches on the cable P3 connector which can allow partial or intermittent connection at one end of the connector.
Also as the NIS is red-lighting all together (all LED's on) suggested that it cannot find the presence of a loop or the NIS TU is not connected, as suggested earlier. I single node still needs a loop of at least >3 ft (~1mtr) length.