Does the fuse blow without the Plasma Display connected? If not, you may need to replace the display; I would replace it with a low power LCD or LED display at which point you will not even need the DMD power board.

This is an interesting guess; I'm curious as to what brought you to this conclusion? And why not C1?

IMO this board is not cost effective to repair; this is based on the 50% rule which is that any item that costs over 50% of the new purchase price should be replaced; as a board repair guy I don't like this at all, but unfortunately this is the world we live in.

Since I would charge a minimum of $35 to test the board (not repair) you have already met this 50% threshold as you can purchase a new board from Marco for $70, plus you have to pay shipping both ways; this doesn't even address the possibility that the board may test 100% operational in which case you are out around $50 and are no better off.

Link to replacement board:
https://www.marcospecialties.com/pinball-parts/520-5138-00

If it turns out you plasma display is bad and you decide to replace it with a low voltage display, I made a post in the LOTR forum about a year ago on how to completely bypass and remove this board from your machine; here is the link to that post:

https://pinside.com/pinball/forum/topic/the-lord-of-the-rings-journey-begins-members-club/page/61#post-4442968

I think I see how you can come to that conclusion looking at only this board and not seeing the bigger picture on how this board ties into the rest of the machine.

This entire board is essentially nothing more than a rectifier/regulator in that it takes two AC inputs to provide 3 DC outputs. The fuse itself is actually bonded to tied directly to both the 88VAC and 110VAC equally as it provides a center tap to the transformers secondary windings which is bonded to ground on the board as shown below.
pasted_image (resized).png

The schematic was also missing some important output information which may have helped to show how the fuse actually prevents overcurrent condition of all three DC voltages (-120, -100, and +60) as the current path must return to the transformer via F1.

This is a very simplified current path as it ignores all of the regulation and filtering of the AC voltages that the board performs.
pasted_image (resized).png

No, you should be able to check the diodes as well, you are essentially looking for a dead short so it should be fairly clear which part is bad. If D1 or D2 becomes shorted, then you are going to loose D3 or D4 respectively as they will likely become shorted as well.