I've done similar to a part on my dryer's control board, and a GPU's vram. In both cases, there was no diagnostic needed because the part showed some kind of physical damage. You would be surprised how often things can be fixed for 1% the cost of replacing.
You got it correct there. If it's junk, open it up, and take a look. It might be obvious. Given the rising cost of stuff like GPUs, this could become more relevant.