For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
Make sure your LCD is good. Seen a ton of these gen1 A1398 units that had bad LCD panels that mimicked a hard system freeze (cursor freezes, etc). Sometimes it would be from motion/movement of the display, other times it seemed to be random. Tricked a ton of our retail customers (would "swear" it's a board issue, but it was a panel failing). Won't necessarily have any sort of display anomaly (lines or weird colors or anything) or trip AHT/ASD failure, etc.