Optima/Hammerhead Primary Handset Failure During Dive?

diveladydive · 9th May 2008, 03:29

Quote: (Originally Posted by jradomski)

There are different issues here...

The first is that prior to the last update for the al handsets - around nov 2007 (delrin had the fix when they were released), when the system rebooted, the solenoid would be activated regardless of what the po2 was.. It takes several seconds to get a valid po2 reading, prior to this the system saw it as a low po2, so it injected..

This has 2 effects.. if its a marginal battery, this can cause the system to reset again especially if the diver tries to do anything on the handsets.. This will compound the problem..

The dead/reset issue if at a constant depth its USUALLY a dead cell, if it happend on ascent its usually a poor contact..

The contact issue is best solved by using a compound like noalox to prevent the formation of al-oxide.. and making sure the threads are coarse (you should feel some resistance when screwing the battery cap in)

The released delrin unit have never had the oxygen on reboot issue, the ss cap has solved the contact issue most of the time.. its not perfect and probably will never be since the mechanical contacts are subject to stresses due to case compression.. The way to cover the very rare issue here is to use a silver conductive lubricant on the battery threads, and both battery contacts..

Batteries/cells were replaced just in case that was the issue between dives, but millivolt readings were strong. Possible contact issue, as I mentioned- that's where opinion comes into play. However, I had used conductive lube prior to diving the unit. Whatever the actual reason (will never know for certai, as all the experts disagree on various conceptualizations...

Your advice should be taken into serious account- batteries on the way down have a bad habit of doing unexpected things, contacts are critical & should be kept clean & checked, cells readings, as well as all other pre-dive checks, are also critical, & your life may depend on your topside vigilance.

Rebreather divers should also be aware that certain units will spike PO2 on a fast drop- usually not dangerous, but you need to be trained to differentiate a reason to call a dive due to high/unstable PPO2 readings vs. a spike, which quickly drops.

diveladydive · 9th May 2008, 03:32

Not full tech penetration- ambient light only, relatively easy dive, & staged properly.

The instructor was Tom Mount, who is about the best I can think of.

All individuals on the dive agreed to the dive plan. It was actually quite conservative.

SiscoKid · 9th May 2008, 18:56

Quote: (Originally Posted by diveladydive)

Not full tech penetration- ambient light only, relatively easy dive, & staged properly.

The instructor was Tom Mount, who is about the best I can think of.

All individuals on the dive agreed to the dive plan. It was actually quite conservative.

Souds like my kind of diving.

diveladydive · 10th May 2008, 03:36

Quote: (Originally Posted by SiscoKid)

Souds like my kind of diving.

!

Peri

9th May 2008, 03:29	#31 (permalink)
diveladydive New Member Current Rebreather/s: Optima Pelagian Other Rebreather/s: Megalodon Optima Titan Pelagian Join Date: Jan 2007 Location: Southeastern Florida Posts: 50	Re: Optima/Hammerhead Primary Handset Failure During Dive? Quote: (Originally Posted by jradomski) There are different issues here... The first is that prior to the last update for the al handsets - around nov 2007 (delrin had the fix when they were released), when the system rebooted, the solenoid would be activated regardless of what the po2 was.. It takes several seconds to get a valid po2 reading, prior to this the system saw it as a low po2, so it injected.. This has 2 effects.. if its a marginal battery, this can cause the system to reset again especially if the diver tries to do anything on the handsets.. This will compound the problem.. The dead/reset issue if at a constant depth its USUALLY a dead cell, if it happend on ascent its usually a poor contact.. The contact issue is best solved by using a compound like noalox to prevent the formation of al-oxide.. and making sure the threads are coarse (you should feel some resistance when screwing the battery cap in) The released delrin unit have never had the oxygen on reboot issue, the ss cap has solved the contact issue most of the time.. its not perfect and probably will never be since the mechanical contacts are subject to stresses due to case compression.. The way to cover the very rare issue here is to use a silver conductive lubricant on the battery threads, and both battery contacts.. Batteries/cells were replaced just in case that was the issue between dives, but millivolt readings were strong. Possible contact issue, as I mentioned- that's where opinion comes into play. However, I had used conductive lube prior to diving the unit. Whatever the actual reason (will never know for certai, as all the experts disagree on various conceptualizations... Your advice should be taken into serious account- batteries on the way down have a bad habit of doing unexpected things, contacts are critical & should be kept clean & checked, cells readings, as well as all other pre-dive checks, are also critical, & your life may depend on your topside vigilance. Rebreather divers should also be aware that certain units will spike PO2 on a fast drop- usually not dangerous, but you need to be trained to differentiate a reason to call a dive due to high/unstable PPO2 readings vs. a spike, which quickly drops. __________________ *Complacency: Self-satisfaction especially when accompanied by ignorance of actual dangers or deficiencies.* *Success: A journey in which the improbable becomes possible, leading to surprising levels of achievement.* *Dr. Peri M. Blum* *Instructor, IANTD* *Member, Board of Advisors, IANTD* *www.supremedivers.com* *561-901-9715* The opinions expressed herein are those of the author and the author’s alone. Last edited by diveladydive : 9th May 2008 at 03:30. Reason: grammar
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9th May 2008, 03:32	#32 (permalink)
diveladydive New Member Current Rebreather/s: Optima Pelagian Other Rebreather/s: Megalodon Optima Titan Pelagian Join Date: Jan 2007 Location: Southeastern Florida Posts: 50	Re: Optima/Hammerhead Primary Handset Failure During Dive? Not full tech penetration- ambient light only, relatively easy dive, & staged properly. The instructor was Tom Mount, who is about the best I can think of. All individuals on the dive agreed to the dive plan. It was actually quite conservative. __________________ *Complacency: Self-satisfaction especially when accompanied by ignorance of actual dangers or deficiencies.* *Success: A journey in which the improbable becomes possible, leading to surprising levels of achievement.* *Dr. Peri M. Blum* *Instructor, IANTD* *Member, Board of Advisors, IANTD* *www.supremedivers.com* *561-901-9715* The opinions expressed herein are those of the author and the author’s alone.
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9th May 2008, 18:56	#33 (permalink)
SiscoKid New Member Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: Farmersville Texas Posts: 68	Re: Optima/Hammerhead Primary Handset Failure During Dive? Quote: (Originally Posted by diveladydive) Not full tech penetration- ambient light only, relatively easy dive, & staged properly. The instructor was Tom Mount, who is about the best I can think of. All individuals on the dive agreed to the dive plan. It was actually quite conservative. Souds like my kind of diving.
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10th May 2008, 03:36	#34 (permalink)
diveladydive New Member Current Rebreather/s: Optima Pelagian Other Rebreather/s: Megalodon Optima Titan Pelagian Join Date: Jan 2007 Location: Southeastern Florida Posts: 50	Re: Optima/Hammerhead Primary Handset Failure During Dive? Quote: (Originally Posted by SiscoKid) Souds like my kind of diving. ! Peri __________________ *Complacency: Self-satisfaction especially when accompanied by ignorance of actual dangers or deficiencies.* *Success: A journey in which the improbable becomes possible, leading to surprising levels of achievement.* *Dr. Peri M. Blum* *Instructor, IANTD* *Member, Board of Advisors, IANTD* *www.supremedivers.com* *561-901-9715* The opinions expressed herein are those of the author and the author’s alone.
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