[evlatests] touchy L302s

[Jim Jackson]

Steve and I noticed this behavior in some tests we did on the L302's in the 
antennas a few weeks ago - after the symptom was apparent in Rick's long 
test over the holiday weekend in January.   We replaced the L302 that was 
doing it the most (I think that was L302-1 in Ant 14) but we did notice it 
occurring less often in at least two of the other L302's in antennas 14 and 
16. Unfortunately, the four L302's that are out in those antennas are the 
best of the old style units.  Can anyone tell for sure if the L302's in 
antenna 13 are doing the same thing? I'll check them today but it would be 
interesting to see if the data shows them doing this.  Antenna 13 has the 
newer design that uses the L300 but they still have the same firmware as 
the others.

I can repeat the test today using Jared's Labview software to see if it has 
gotten any worse. We can exercise them fairly hard with this software and 
see graphical results of what is occurring.  Before attempting to isolate 
this problem, we are waiting for the new FPGA and MIB firmware that Matt 
Luce and Pete Whiteis are working on. It would be a waste of our time to 
time to troubleshoot this before having this new firmware.

Jim




At 11:33 AM 2/12/2006, Ken Sowinski wrote:

>It is clear that the failure of 16 AC at L band which I
>reported Friday is an L302 problem.  Vivek reports it
>went away for a while,  but it is back again today.
>
>Vivek supplied a file to exercise the antennas during
>Rick's time this morning and I used the beginning to
>be sure that all still worked.  16AC was dead at C band,
>the L302 was in standby and rebooting fixed it.  Moments
>later when Vivek's file started it was again in standby.
>It complains that the main loop does not lock.
>
>My guess, but no prove at the moment, is that this is what
>happened to cause 14BD to be reported as not working Friday
>night.  It should be possible to learn from the monitor data
>base whether or not ea14-l302-2 was out of lock during the
>Friday night/saturday morning test.
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