Chosen Solution
MBP 2012 A1278 2.5Ghz Dual Core Intel Core i5-3210M System works fine when connected to power and battery is disconnected. However, when battery is connected, the system displays lines and spots. Some times screens hang. I am told by Apple Service that the logic board needs replacement and cost is almost what i paid for the system when I bought it new. Is it worth replacing the board in 2020? Can this issue be resolved some other way?
I think you have a more basic issue which can be easily fixed. Are you up to fixing your own system? If you are let’s get to it! Using this guide to help us walk through things MacBook Pro 13" Unibody Mid 2012 Logic Board Replacement follow the first steps to disconnect the battery (stop as Step 4). Now lets jump down to Step 15 carefully disconnect the LVDS cable and take some pics of the logic board connector as well as the cable so we can see the solder joints and pins.
