Phillips HDI5000 error 0087!!!! Need help

Local customer had there HDI5000 go down, issue turned out to be a bad PCM board which i replaced then updated the system. It has since been sitting and now is ready to return to the customer. When i went to test again before taking to customer i got an error message i hadnt seen before--- 0087 Now i understand 87 is a software issue, but i have been told by a company assisting me that if there phillips cmos mattery is dead i could see this issue. Upon removing this battery i noticed it wasnt a common batt. Its an ibutton that has data threw put. The voltage of this is .3V, which i assume is suppose to be around 3V. Can i just swap the ibutton battery for a new one or is there a special procedure to replace this battery? Any help is very appreciated, really need this unit running ASAP.