Tekna dive computer question

Hi,

I have a Tekna Computek dive computer from around 1990. However, I
took the old battery out when I put the computer in storage so it
wouldn't ruin the computer (as I do with all battery operated things I
put in storage), however I can't find where I put the old battery and
after several trips to different dive stores, nobody is able to sell
me a battery because they don't know what battery it takes. None of
them have an old Tekna manual or reference chart. Tekna has been out
of business for some time, so I'm hoping someone with a Tekna dive
computer can help me out or point me to a store where I can purchase
one. One of the stores I stopped at had a couple of batteries that
looked like a close fit, but the voltages of the two batteries were
different and I didn't want to guess and possibly fry the dive
computer. Any help would be appreciated.

Thanks,

Tony
tonyj@execpc.com