HOW DO I GET A REPLACEMENT FOR MY 2013 MACBOOK PRO FAULTY MOTHER BOARD

Start here: https://getsupport.apple.com/repair-locations

Apple is not likely to have any replacements on hand for a ten year old Mac, but an independent repair shop might have a source. Bear in mind any replacement logic board you may find is going to be just as old as your existing one.

Servant of Cats raised a very good question. Read If your Mac doesn't turn on - Apple Support and If your Mac doesn't start up all the way - Apple Support before prematurely concluding the logic board is the sole cause of an inability to start your Mac.

A logic board, even if you decide you need to replace it and can find one guaranteed to work, simply is not likely to be an economically justifiable repair.

I also think it's likely that you will have trouble finding a replacement logic board.

As far as saving data that wasn't backed up, all of the 2013 MacBook Pros used flash storage. The Early 2013 models appear to have used SATA SSDs. The Late 2013 models appear to have used PCIe ones. Other World Computing sells replacement SSDs and external transfer enclosures for the Late 2013 models.

So it sounds like it should be possible to remove the SATA SSD or PCIe circuit board SSD from your 2013 MBP, place it into an external enclosure, and attempt to recover the contents using another Mac. This might be a way to proceed if you cannot find a replacement logic board, or the cost of replacing the logic board would be too high, relative the cost of replacing the computer. Maybe the data on the drive can be saved, maybe not – but if you can remove it and put it into an enclosure, at least you can try.

Note that on some computers with flash storage, the SSDs / flash chips are soldered directly to the logic board, and thus replacing the logic board wouldn't save your data. I believe that current Mac laptops are like that, underscoring the importance of keeping proper backups.

I took it to a second guy and he ran a diagnostic for $100. He said the mother board and the video are problems and I could get a mother board for $700. I had just spent $225 so I'm not willing to spend twice as much more only to be sick, again!! (I loved this 2011-I2) I had run the online test as had the first guy who changed the memory card to a larger capacity. (stated in previous email) The only other thing he did was download the newer operating system to High Sierra. I thought I had tried that a few years back but maybe I didn't have enough memory a the time. Maybe his getting more memory allowed him to download High Sierra. Every other time I got the upgrade notice, I'd had no trouble.

Also – if the MBP is not turning on, how do you know that it is the logic board that is shot, rather than the battery?

[Ignore – didn't realize that this was an old thread that got bumped.]

Get help from an Apple Store or an authorised service provider. Do this as quickly as possible, your MacBook Pro will run out of time to be saved.