[evlatests] [widar-wg] PTC problem status

[Jim Jackson]

We believe the PTC problem should be fixed.  Please let us know if 
the problem reappears.

The main problem seemed to be related to the 1PPS signal from the 
VLA.  It is a TTL 50 Ohm drive digital signal from the L35 that was 
being split two ways with an RF splitter.  One side fed the L350, the 
other went to the VLBI racks.  When Leon and I were measuring 
everything the other day, everything seemed to be working. After we 
finished and put it back together, Ken almost immediately called and 
said it was broken again. I realized the only thing we did was 
reconnect that long cable to the VLBI rack. The next morning, we 
disconnected the cable again and the light went back to blinking 
green.  We rerouted some things and now have those two signals being 
fed from separate line drivers with no splitter. The time code board 
seemed happy after that.

We also updated the firmware in the L350 as I described in a previous 
message.  This should make it more immune to problems with the 1PPS 
in the future.

Jim