Help please with old SP bottom timer

[awap]

Last Scubapro kit that I picked up on ebay included a SP bottom timer. It looks like a large watch with no hour hand. It has a rotating scale graduated in minutes. In the back, there is a rubber seal that is just the right size for a watch battery. I'd like to understand how it works and how to change the battery. I assumed it is water activated but it didn't do anything in the sink. So either the battery is dead or the switch requires contact and pressure. Any help would be appreciated.

Thanks

[DA Aquamaster]

I think most of the old dive times were pressure activated at about 6 fsw. Most were also required to be sent back to the factory for battery replacement as the sealed case usually required total replacement. I did get a few more years out of my Tekna digital bottom timer after factory support ceased by cutting a hole in the case over the battery (it had a clear case which helped the surgical process immensely). I then filled the battery compartment with a silicone calk.

Mine also had a "rubber seal" but it was the depth sensor that activated the timer. I suspect your Scubapro may be the same and removing the rubber seal may destroy your dive timer.

I do not have any techical stuff or specs on the bottom timer but I can ask the SP tech services folks. If you have an SP dealer near you they can do the same.

[awap]

Thanks, I'll give the local dealer a try. But first I better put it on the bottom of the pool. I may be pleasantly surprised.