Ｍｏｎｉｔｏｒ，
Ｉ　ｄｅｃｌａｒｅ　ｙｏｕ　ｔｏ　ｂｅ
ＦＩＸＥＤ，　ｈｅｎｃｅｆｏｒｔｈ！

(It was the 2SA953 transistor in the pincushion deflection circuit, the 2SC945 in the same circuit, and the M51387 video amp chip, as I expected.)

@wyatt 8^y

the 51387 chip wasn't actually marked as "M51387P" btw, it didn't have the mitsubishi logo or the "M" at the start. It was just marked "51387P" and I guessed based on looking up similar part numbers, noticing that the printing was on the same position on the package, and that the package itself had the same looking moulding.
I wonder if Mitsubishi just wasn't marking them at that point, they had some special arrangement with NEC, or what?
The printing was also VERY faint on the original chip, as though it had been washed or something.

@wyatt Oooh, cool monitor is fixed!

@evgandr yup, since i was the one who broke it that made it pretty simple to figure out what i killed in it based on proximity to the parts i shorted (combined with the symptoms of extreme pincushioning and extremely dim video). Video amp IC (M51387P) and two transistors (2SC945 and 2SA953).