How do you use the mic otherwise? (Videos, speakerphone, . . .)

Seems like you got a bad battery. Just look into a RMA with iFixit. Im sur given your proof theyll assist you.

Im experiencing the same issue and I suspect it is possibly because of overheating.

You must first turn this laptop off. The only possible repair would be cleaning by completely dismantling this laptop to get to the motherboard. At that time you must inspect and clean your motherboard with alcohol and a toothbrush. If you have access to a ultra sonic cleaner, you can also clean inside of that but I still suggest brushing off the visible corrosion on the board with a toothbrush and alcohol first and then putting it in the cleaner. After you have cleaned the board then you want to make sure it completely drys, I suggest using a dehydrator. At this point you want to check the casing of the laptop and all the connectors that would connect to the motherboard coming from harddrive keyboard monitor etc. for corrosion and clean those off as well ( brush off with alcohol, dry off). It's a long process but if done correctly and if you system isn't all ready damaged beyond repair you should be able to have a working computer that you may have to order only a couple part replacements vs and entire...

Sounds like it could be many different things. You could be experience battery, charger dock, screen or motherboard issues. First you want to make sure the problem isn’t the charger cable, block or outlet before moving on to repair options.

This repair price will vary per repair shop and the reason being because this is a soldering job. The part itself cost will cost no more the about $6-$12 but the ability to have some one desolder the old port and solder the new port on. At my shop this wouldn’t be anymore then about 129.99 dollar repair but then again we solder things all the time. (HDMI Replacements, Charger ports for tablets, iphone IC chips, etc.) The repair shop you went to is probably charging you for an entire new computer or new motherboard. The link below show a similar repair to what you would have to do if you feel comfortable doing it. https://www.youtube.com/watch?v=P_2OREOz...

Has the device been dropped before or has this phone had parts replaced? And or has this device been exposed to liquid?

First I would try and boot from a known good copy of the MacOS from an external drive. Do this by holding the option key once you turn on the macbook until you see HDD icons.

You have to disassemble the device. Make sure to order the correct part. Here’s a link to the ifixit walk through. iBook G4 12" 800 MHz-1.2 GHz DC-In Board Replacement Here’s a link to the supplier I use from time to time. http://www.powerbookmedic.com/

This sounds like your LCD has gone bad. The green lines you describe are what give it away. You can attempt to do a Glass/LCD replacement but keep in my the sub keys next to the home button are glued to the screen so be very careful.