Aladin pro dive computer battery replacement

[ggchab]

A friend of mine owns an Aladin pro with an almost dead battery. There are several videos on the net showing how to replace it.
(https://youtu.be/Gp8YvelU-3Y)

I was a bit surprised by the paraffin oil (even if I understand why it's required) but otherwise, the operations are quite obvious except the reset procedure.
They use a 3V battery and have to "repeatedly and quickly" touch 2 contacts until the reset is done or ... the unit is dead   

Any idea of what this is really doing ? Is it possible to use a function generator to send a specific sequence of pulses instead of that obscure procedure ? Or something else ?

Thank you for any suggestion.

[GeoffreyF]

Filling electrical/electronic components with oil is commonplace. The general reason is that the oil is not compressible and thus there is no reason for a heavy metal case to resist the pressure.  In this particular case, it also allows communication of the ambient pressure through the case, and the diaphragm you see re-installed, so the pressure can be accurately sensed.  Tracking pressure changes and time is the basic function of this device.

It should be noted that working accurately and reliably is essential to the divers health and life. Some types of diving absolutely require this reliability and others, less so.  A diver may be making critical decompression decisions in relation to his or her remaining air supply.  Without the computer, they simply can't return to the surface without guessing what should be accurately tracked and computed.

Once the work shown in the video is completed, the computer should be put in a pressure test chamber. Many dive shops have them. There it should be put through it's range of pressures, compared to a known good pressure measure, and then through a range of pressures as though for typical dives, to verify that the instrument works as it should.  Actually measuring pressure and assuring the thing does not fail under pressure MUST be done.  The diver can decide if they want to trust the thing based on this testing.

FYI - I am a retired dive instructor trainer as well as someone who has worked professionally with electronics.

[ggchab]

Thank you for the additional information.
Any suggestion about the reset procedure ?

[rstofer]

Some ScubaPro dealers provide service for this dive computer and considering its purpose, I would think professional service is the way to go.

I wouldn't think this is a place for the DIYer.

[ggchab]

Ooops, I choose the wrong section  Could someone move this topic to "Repair" ? Thank you

[ggchab]

Some ScubaPro dealers provide service for this dive computer and considering its purpose, I would think professional service is the way to go.

I wouldn't think this is a place for the DIYer.

You're probably right.
My friend already bought a new dive computer. So, I guess if he wants to repair the old one, it will be used as a backup only. Or he might know someone who can test it...

[IDEngineer]

I've been Open Water certified for 40+ years. I'm a hardcore DIY'er, almost to a fault, but this is one area where I'd defer to the professionals - perhaps even to the point of sending the unit back to the manufacturer for battery replacement and recertification. Or, depending upon how old the unit is, retiring it with thanks for its life of service and taking advantage of technology advances that have taken place in the meantime.

Diving can be serious, life-risking business. If you are literally trusting your life to your dive computer (rather than doing the calcs by hand via table like the old days) you shouldn't take shortcuts with it!