PowerBook G4 15” Won’t turn on at all

My PowerBook G4 won’t turn on. I plug in my power adapter (came from amazon, says it’s 65w) and get no response. This power adapter work fine in my iBook G3. The PRAM battery is still good, but the main battery is totally and completely dead. When plugging in the power adapter, I get a voltage reading from the battery terminals. I tried bridging solder pads on the logic board, but it still didn’t start. I tried resetting the PRAM and SMC but to no avail. Does this sound like a power adapter issue not supplying enough wattage, or something else? Thanks