diagnosis: a dissolved connector pin

Mike Shoemaker makes this report about the likely cause of the station's power problems:

These are the preliminary results of the examination of returned instruments from Saipan. The attached pictures are from the PAC IOOS CT main power Y-cable which provides power to the instrument and the attached water pump along with communication. The connector that attaches to the fish bite cable adapter has had a pin arced off. This pin is still embedded in the adapter. I speculate that this may have been caused by bringing the instrument up to the surface to disconnect from the station and connect to a laptop for download then being re connected without properly drying the connectors and lubing with silicon to form a proper seal. In addition to these problems the strain relief connector is missing from the main fish bite cable, this also could be the cause of the seawater intrusion as that the main fish bite cable megs out @ infinity but when the adapter is attached it megs out @ 1.5meg.

The BIC _DP cable megs out @ anywhere from 400meg to 600meg depending on which of the 4 conductors that you attach to and the CTD_DP cable megs out @ 200meg across all 4 conductors. I speculate that from the earlier e-mail from Mr. Benavente about the three prong spears used by local fisherman that the cables were punctured from these and that seawater intrusion has caused these high resistance short circuits.

My next step will be to see if Mr. Bishop has any of the Y-cables left from the Sea Bird CTD's that we transferred to his group to test the PAC IOOS CT and down load Gordon Walker's data along with testing the other returned underwater instruments. That is unless Gordon can expedite a shipment of a cable from his spares.

As Shoe explains, we now believe with a high degree of certainty that the station power problems were caused by a connector failure.  The ground pin from the PacIOOS Y-Cable is missing in the connector that attaches to the CREWS pigtail adapter.  Both this Y-Cable (a SeaBird part) and the pigtail adapter (custom-made by CREWS) must be replaced.

Next steps will include downloading the PacIOOS on-board memory and re-testing of the "brain" components.  The underwater sensors that have been retrieved, since they were deployed on the station for more than a year, will now be sent back to their manufacturers for evaluation and recalibration, and the station will next go live with its alternative set of sensors (most of which have been in storage in Saipan since August of 2011).

Clicking on any of the images below should load a full-sized version.

Mike J+

station equipment reaches Miami

Following the last blog update on September 5th (which mentioned how the station had been completely offline since August 24th), the station resumed its brief sunlit periods of activity for a few hours a day until September 19th.  The last coherent report from the PacIOOS CTD, however, occurred on September 10th.

I'm not sure of the details of timing and personnel, but I believe David Benavente and Steven Johnson were involved in an operation on September 27th, 2012, to retrieve all of the station underwater sensors and cables as well as the "brain" package.  These, along with the "groundtruth" CT, were packed up and shipped to AOML in Miami on September 28th.  The shipment arrived here on October 1st, 2012.

David Benavente had made the following observation about removing the instruments from the station:

So just thought you should know. While I was attempting to shut down the PACIOOS Seabird I removed the male/female plugs to connect it to the serial port. I noticed that one of the copper nodes on the male side had corroded off. Im not sure if its the ground wire, but I thought I should let you know. I decided to remove the batteries from the PACIOOS CTD so that it cannot continue to collect data.

Mike Shoemaker will be leading the effort to diagnose the power losses that have plagued the station in the past few months.

Mike J+