NEC XM29 fuzzy picture with max horizontal setting

[Atari FGC]

I'm having with the horizontal width on one of my XM29s, and was wondering if anyone here might be able to help. Basically, if I try to fully open the horizontal width, the picture gets fuzzy. It wants to be a much smaller picture that doesn't fill up the screen and if I shrink the size, it's ok, but even getting close to fully widened, it gets fuzzy. Placing a magnet on one of the transformers transformer does help, but it doesn't entirely fix the issue as I cant fully open the horizontal and when I max the width, it causes fuzziness.

I've had it with a repair guy for over two years. He's working on it sporadically but hasn't made any progress, so I'm hoping folks here might have some ideas.

 

[Atari FGC]

Update: I spoke with the guy today to clarify what has and hasn't been done. He has NOT recapped the chassis (believes that to not be an issue because heating everything up isn't having an impact), and he has NOT changed the horizontal transistor (believes this to not be an issue because it's registering high voltage). He has been focusing on the horizontal pincushion circuit.

If anyone here has thoughts or ideas, I'd love to hear them as it's been at the shop for over 2 years! I'd just really like to get this monitor back, working.