Scubapro Helium Depth Gauge- how does it work?

[Darkforeboding]

I bought a Scubapro helium depth gauge on E-bay for $12.55. It was $20 by the time I got it shipped. Got it and it doesn't work.

Can anyone tell me how these things work? Was it helium inside a diaphragm? Does it have a bourdon tube? Is it supposed to be oil filled?

Here's a picture if I can get it to post.

DFB

 

[Luis H]

It is not oil filled. It is just gas filled.

Did you try it in the water or in a pressure chamber or did you just try pushing on the surface? If you just tried pushing on the surface the needle will not move. The pressure sensing diaphragm in on the back behind the loop that holds the strap.

I would be surprise that it doesn't work if you actually tried it in the water (or a pressure chamber). Most vintage depth gauges are not very reliable (as opposed to vintage regulators which many tend to be extremely reliable), but this one in general is the exception. This depth gauge is from the 70's, and it is the only depth gauge from that era that has a great reputation for still being very reliable and accurate. Of course it is always possible that yours is broken.

I have two (or three) of those and I have only tried one recently and it worked fine.


BTW, IIRC, the screw on the top surface is just a plug (with an O-ring) that you would open for a moment to equalize the pressure if you were going to dive in a high altitude lake. Obviously you have to make sure it is sealed before you in the water.


Good luck

 

[Darkforeboding]

Yeah, I have a clear lexan pipe and put the depth gauge in the bottom, then filled the pipe with about 5 or 6 feet of water. I was only looking for deflection of the needle, but I didn't get any.

I considered that maybe it just hasn't been used in so long that the mechanism might be stuck. I plan to try it sometime in the next few days somewhere deeper to see if it frees it up unless someone has a better idea.

DFB