Cobalt kept shutting off during the dive

[otomerat]

On today's dive I thought that things were going normally, but noticed that my Cobalt screen went blank (black) during the dive. I hit the Select button and the Cobalt screen came on showing the normal information, such as depth, psi, etc., except the dive time was zero.

This happened over a 1/2 dozen times during the dive. Each time everything looked normal after the Cobalt 'woke up', except the dive time showed zero. After the dive I checked the dive log and the dive was not logged.

DiveOS: V.1.42/2 Battery at 91% at the time, now it's at 88%
Once at Home I put the Cobalt into Sleep mode and dipped the tip into a bucket of water and it woke up in Dive mode.

Any ideas about what may be wrong?

 

[RonR]

This sounds as if your Cobalt did not see that it was wet during the dive. It would show pressure and depth under those circumstances, but would not start a dive and would go to sleep mode after five minutes. It sounds as if you are able to wake it repeatedly, but the dive time being zero means it didn't see water contact. Sensing water is necessary for it to start a dive.

Sometimes this has happened because the pins where you plug in the USB/ power adapter were coated with something (oil or grease, suntan lotion...) that kept them from seeing water- those pins are where water is sensed. A good cleaning might help. It's possible, but not very likely, that this could be something internal where contacts are getting interrupted. There is a spring that makes contact between the PCB and the pins. The fact that you were able to wake to the dive screen with water contact shows it was working at home, so whatever is going on is intermittent.

Try cleaning the pins with soap and water, is if there is anything that looks unusual. The pins should be bright silver stainless steel. If not, PM me and I will help with troubleshooting.

Just to cover all the bases, let us know if you have been diving it for a while.

Ron

 

[otomerat]

This sounds as if your Cobalt did not see that it was wet during the dive. It would show pressure and depth under those circumstances, but would not start a dive and would go to sleep mode after five minutes. It sounds as if you are able to wake it repeatedly, but the dive time being zero means it didn't see water contact. Sensing water is necessary for it to start a dive.

Sometimes this has happened because the pins where you plug in the USB/ power adapter were coated with something (oil or grease, suntan lotion...) that kept them from seeing water- those pins are where water is sensed. A good cleaning might help. It's possible, but not very likely, that this could be something internal where contacts are getting interrupted. There is a spring that makes contact between the PCB and the pins. The fact that you were able to wake to the dive screen with water contact shows it was working at home, so whatever is going on is intermittent.

Try cleaning the pins with soap and water, is if there is anything that looks unusual. The pins should be bright silver stainless steel. If not, PM me and I will help with troubleshooting.

Just to cover all the bases, let us know if you have been diving it for a while.

Ron

I usually do two dives every weekend. But in the last month only managed 4 dives because of a vacation and work. After the dive day I download the dives to my PC and charge my Cobalt at the same time. So, the pins should be clean. They're hard to see clearly, but the tips look clean and they look like they're free of any corrosion.

I think that I may have an intermittent problem. When you mentioned the USB/power adapter I plugged the power adapter side (not USB side) into my Cobalt just to help clean the contacts. Doing that woke up the Cobalt into Dive mode. I tried that a few times and it happens (almost) every time which may be normal. But at one point it quit waking up into dive mode. That's why I say it sounds like an intermittent problem. I'll PM you later today.

 

[RonR]

Yes, if the Cobalt is asleep it would be normal for inserting the power adapter to put it into dive mode- it bridges the same contacts. If that din't happen it could be abnormal, and very possibly related to the fair to enter a dive.

Ron

 

[Akimbo]

Would a failure to detect the pins being wet prevent the decompression and logging functions to kick-in? Is it only programmed to suspend the sleep mode?

 

[RonR]

Would a failure to detect the pins being wet prevent the decompression and logging functions to kick-in? Is it only programmed to suspend the sleep mode?

It takes both wet contacts and pressure change to start a dive. If it doesn't see wet contacts the Cobalt won't start a dive- this prevents self diving in situations like descending in a plane, or coming down a mountain road. And if a dive does not start, it isn't running any decompression calculations or logging a dive. The Cobalt is always sampling and storing the ambient pressure so it knows correct surface pressure when a dive does start, but that is transparent to the user.

Once a dive begins, it won't go into sleep mode until after it is ended. If the water contacts are wet and a dive hasn't started, it won't go into sleep either, but can go into a "standby" mode where the display shuts off to preserve battery power. In standby it is still sampling pressure rapidly so we can detect the start of a dive quickly.

Ron

 

[Akimbo]

OK, maybe I misunderstood. I am under the impression that the OP was able to read deco info and download the log of the dive. If that is correct wouldn’t that indicate that it was going dark even though the Cobalt was actively in dive mode?

 

[RonR]

OK, maybe I misunderstood. I am under the impression that the OP was able to read deco info and download the log of the dive. If that is correct wouldn’t that indicate that it was going dark even though the Cobalt was actively in dive mode?

No, he did not see any dive time or NDT, and the dive was not in the log. That would indicate the dive didn't start, and the Cobalt was just going into sleep mode. It did show depth and tank pressure, which it will do even when not in a dive. In a dry chamber we have to bridge the contacts to make the Cobalt think it is diving. On subsequent tests there were some instances of this Cobalt not sensing water at the contacts, so there is or was a problem there. The behavior is consistent with poor contact between the water/ pins and the internal circuitry. We are still trying to diagnose exactly where the problem was, as it seems to be working now.

Ron

 

[kroorda]

One of my previous Cobalts did the same thing and Atomic ended up replacing it, as it couldn't be repaired. The new Colbalt they sent leaked. They replaced that one. Now, my wife's Cobalt intermittent shows that the air pressure is 0 and she must abort her dive. Virtually every person I know of (including myself) who owns a Cobalt has experienced failures. It's a nice computer WHEN it works, but one should not own a Cobalt without also owning a backup computer.

 

[RonR]

Krooda,


I’d like to help you get this fixed. It sounds as if you have had unusually bad experiences. What version is your wife’s, a Cobalt 1 or 2? And what firmware version? Is this something you have always seen with it, or did it just start happening?


If the tank pressure display drops to zero when there is still gas in the tank, and other information such as depth, dive time, and compass heading are still displaying properly, that is likely due to either a broken or damaged wire between the tank sensor and the main PCB or a bad high pressure sensor. This should be easily repairable, though often Atomic choses to replace units that have had problems so as not to delay getting the customer back in the water. Unlike the OP’s problem, this is something with a clear diagnosis.


I would encourage you to contact Atomic to get this fixed, the tank pressure reading should be 100% reliable. I'm happy to help in any way I can.

Ron