Stick thin nose pliers or similar in the 2 dents in the round end cap and unscrew
Remove cap and O ring, Inspect O ring and if Fine, regrease and place back on cap
Go to Maplins/Radio Shack and buy an AA size Lithium 3.6 volt battery (LR-07)
Unsolder old battery, solder in new battery, direct to base and stub
Replace cap and O ring
Go diving
Cost to do it yourself $7 and 5 mins
Cost for Uwatec kit $45
Cost for LDS to do the same as above $50
I know cos I used to work in a LDS and we used to pop next door to Tandy's (Radio shack). The shop never changed the O rings and never had any problems (they dont move in use)
Obviously not recommended if the warantee is important.
Oh and by the way the Uwatec battery left guage is not a true guge its just a guess based on the hours on, so many go flat with battery still showing good
And for the record, to the person who commented above. Suunto made their first dive computers in 86, over a year before Alladin (Uwatec) so they have just as much experiance (It was called the ME and mine is still fully functional, as is my 87 Alladin Pro (their first computer))
Suunto is not conservative, it uses the RGBM model (like the new Smart Uwatecs), this is because it models solution bubbles as well as theoretical compartments. I'd hazard to say its not that its conservative, its that the other models are not as safe. I certainly feel better using the Vyper for up to 45 mins deco than Buhlmann tables. But have sinced swapped to VR3 and deep stops