The "006c" is the chip location, so changes are its F11 + the one next to it.
A"4264" is a 4164 DRAM Chip. Back then they were sensitive to static and heat (compared to today's chips, they are quite robust), so chances are I'm guessing that who ever soldered the board left too much heat to the chip.
But since you say somebody soldered the board, check to see if traces are shorted with a magnifying glass. One hair-thick sliver crossing 2 pads will will a board.
When I replace RAM on a board, I usually replace the whole set.
A"4264" is a 4164 DRAM Chip. Back then they were sensitive to static and heat (compared to today's chips, they are quite robust), so chances are I'm guessing that who ever soldered the board left too much heat to the chip.
But since you say somebody soldered the board, check to see if traces are shorted with a magnifying glass. One hair-thick sliver crossing 2 pads will will a board.
When I replace RAM on a board, I usually replace the whole set.