Computer miscalculates surface interval!!!

[mbs]

Just getting around to downloading data and trying to understand a wacky problem with my backup computer a few weeks ago in Bonaire. Primary is an Oceanic 200 on my console and a 180 in a hose boot. On the 3rd dive (shore) of the day we came out of the water and while walking to the truck something started a rather loud alarm I had never heard before. Glanced at my primary and saw nothing. Dumped my stuff in the truck and glanced at my backup and it was lit up like the proverbial xmas tree. It had clearly gone into deco and was now locked out. Again, primary fine and my buddies as well.
So first, would it have sounded the same alarm when it went into deco during the dive? I can't believe I would have missed it. I did recall my primary alarming when it went into the 3rd bar of Ni.
Now that I have data loaded it is quite interesting. It appears that the backup has the prior SI as 58.23 whereas the primary has it as 02:58! 3 hours SI makes sense. 58:23? What the heck is that! I have to guess it thinks the SI is 58 minutes. I started the dive on the primary showing 2 bars Ni and on the backup 4 bars. Going thru the data it quickly increases bars and puts me into deco 20 mins into the dive.
Was diving 31% o2. Not concerned that I really did go into deco, but still if I had heard it I would have have respected it and called the dive.
Soooooo, anyone seen something like this, especially on the veo 180? Or any thoughts on the missing alarm at depth?

 

[Tbar]

Could it be a issue with the mount "and a 180 in a hose boot." Some computers use wet contacts to turn on and off, others use pressure. If this boot is not a correct "fit" it may impact with the turning off?

Just a stab in the dark...

 

[redacted]

When you looked at both computers during the dive, did you see anything unusual?

 

[mbs]

Wouldn't expect it to be dry a few hours after the last dive. This was the 3rd dive of the day after lunch.

Never even glanced at the backup. Its just along for the ride should there be an issue with the primary. Only time i might have noticed a problem would have been when i set it for 31%. Had i noticed it 4 bars in or for that matter that it thought i was only out for 1 hour i would have been concerned. But i did not.

 

[Tbar]

My wife had a problem with her back-up once... somehow the altitude had been changed when the O2 mix was set. operator error :/ As a result the NDL was shorter on the back-up device.

But yours seems to be SIT, so I would still look at how it 'turns dive mode off'.

 

[Steve_C]

On some computers you can set it so that they revert to air after a dive or to retain settings. On mine I retain settings during a dive series since I am diving the same mix on both dives. Are your computers set the same?
Are the batteries equally good. If one has a low battery it can shut down between dives and you will loose some information. That could account for the difference in SI.

 

[mbs]

Just weird guys. I,checked the prior dive and the 2 comps match. And the start times match for the offending dive. So other than the si it reports the clock times are correct I have it set to keep the o2 setting between dives. And im pretty sure u cant even set it back to air after diving greater than 21 for 24 hours. I guess ill just have to keep a closer eye on it for a while and just chalk it up to sunspots