I am currently working on a 15" Mac Powerbook G4. After determining that the PRAM battery is bad, I have taken the computer apart to replace it. The model # on the battery board is 820-1819-A. I cannot find this battery anywhere for purchase. My question is, can another model PRAM battery be substituted for this model without any damage to the computer? Thanks.

"I cannot find this battery anywhere for purchase." HUH? I had no problems finding one. Don't use quotes around the part number or the whole string you search with - in this case the A at the end of your part number may merely indicate the supplier that made it for Apple (they didn't make it) or a minor revision, or the A may be ommited in ads for one. Search using: pram g4 820-1819-A (no quotes) Your Pram module, used It says here there are at least three possible part numbers Apple Part #: 922-7173, 820-1813, 820-1819 that will work in what you have - http://www.thebookyard.com/product.... Search using: g4 pram 922-7173 http://ca.search.yahoo.com/search;_... e.g. - A new PRAM module http://www.powerbookmedic.com/Apple... Another part number - 922-6007 "Apple Part #: 922-6007 or 922-7173" A link there - identify your model. Apparently, you have an aluminum 15" G4 powerbook (there are also titanium G4 powerbooks, and aluminum 17" G4 powerbooks, that have different pram modules) Search using: pram g4 820-1813 http://ca.search.yahoo.com/search?p... e.g. http://cgi.ebay.com/Apple-PowerBook... The 820-1813 and 922-6007 pram module looks different from yours, but if it fits, plugs in the same way and is the same voltage, it will work.