Recommendations for pressure testing an AI computer?

[rsingler]

So, if I am able to pressure test with water per rsingler above, would I be correct in assuming that I should first test without battery, and then if that test is OK, then try it with the battery installed and computer powered? My thinking is that if the computer is not powered, fresh water getting into the computer might not fry the electrical components, and could probably be dried out, and a modified hatch cover re-designed. Also, these computers are 7+ years old, but I would prefer not to dive with them until I have exhausted other low cost/risk options.

Most computer battery compartments are sealed off from the rest of the computer. So if it floods, then salt water will short out the battery, dropping current flow to the computer to near zero. That won't harm anything. When testing with distilled water in the pressure pot, flooding won't change electrical delivery to the computer. All you have to do is pull out the computer and see if you see water behind the clear battery door.
If you have an opaque battery door, then the only way to see if your installation was adequate is to pull the door off again, and look for droplets.
Catch-22 - you need to reinstall the door again, lol.
Bottom line: go ahead and test it with the battery in. It won't hurt anything.

 

[Altamira]

Thank you rsingler. Since I am having the battery hatch door designed and manufactured, if it leaks, the computer guy can go back to his drawing board and make whatever corrections are required as long as I don't fry the computer.

 

[rsingler]

You're a motivated diver, preserving that computer. I'd probably go hunting for an old or broken one on EBay, just to use the door. But if you have access to affordable CAD-CAM manufacture, wow!

 

[Altamira]

As I stated in my thread, 3D Printing to solve a computer part problem, the reason that I am trying to have a beefed up hatch cover made is the Aeris AI hatch cover is a crappy design (in my opinion) that has had the same problem with the coin slot breaking on both of mine, and other diver's computers. I did not mind spending $10 or so on an OEM replacement, but they do not seem to be available, and I am not wanting to buy another computer just to get another crappy plastic hatch cover that is likely to have the same problem. Not counting the CAD design cost, I think the finished product is going to be about $25, with a better design and durability. If that works, I am going to be a very happy diver. Right now, I am very annoyed that I have to resort to such measures to save and use my computers, but will be excited if I can avoid being forced to buy new computers for lack of a battery hatch cover.

 

[rsingler]

Which model do you have?
I ask, because the pics of the Aeris Elite T3 battery cover look suspiciously like the Veo or Suunto doors. Have you compared sizes?
Then again, if they're the same, you probably don't want to know after all the work you've put in.

 

[Altamira]

I have the Aeris Atmos AI, and yes, the battery cover looks like those on other computers like Aqualung I550 and Sherwood Wisdom, and probably others. Unfortunately, the threads are ever so slightly different than the Aeris Atmos AI. In fact, I bought three of those Sherwood Wisdom covers, hoping they would fit, but no such luck. I will be sending them back.

 

[dbnewton]

Most computer battery compartments are sealed off from the rest of the computer. So if it floods, then salt water will short out the battery, dropping current flow to the computer to near zero. That won't harm anything. When testing with distilled water in the pressure pot, flooding won't change electrical delivery to the computer. All you have to do is pull out the computer and see if you see water behind the clear battery door.
If you have an opaque battery door, then the only way to see if your installation was adequate is to pull the door off again, and look for droplets.
Catch-22 - you need to reinstall the door again, lol.
Bottom line: go ahead and test it with the battery in. It won't hurt anything.

But is there really any harm is the two step approach proposed? I have always tested enclosures empty first and only after success, add the electronics. I didn't have separate battery and electronics compartments but none the less it still seems a reasonable precaution and only costs one extra cycle in the pressure test chamber.

 

[rsingler]

No harm in it at all, with the small exception of two cover placements:
the battery cover requires careful initial placement, so the o-ring isn't displaced by asymmetric pressure as you rotate the locking ring.
Doing it twice just means two chances to nudge it out of place.
But as an initial check for the OP's new design? Probably a good idea.

 

[RonR]

Dry testing is NOT recommended for dive computers. High pressure air can damage the sensor or the seal. At least, that's what the mfr's say.

We dry test all of our computers prior to wet testing, and from what I know several other manufacturers do as well. I think where this comes from is that one of the largest sensor manufacturers says that very rapid and repeated depressurization in air can "embolize" the sensor's protective gel. But these sensors are also used in many industrial applications where they are exposed to pressurized air.

I love the idea of the Home Depot water filter holder, by the way. One psi = roughly 2' of depth.

Ron

 

[Altamira]

Unfortunately for me, the Aeris Atmos AI owners manual, says not to dry pressure test the computer. I don't know if a one-off test woul damage the sensor, but would hate to go through the effort and expense of having hatch covers made only to screw up the computer.