One of the two things circled in red is your likely culprit.

Unsolder one leg on one first, and if fuse holds put it back and unsolder one leg of the other one. Replace the bad one.

I doubt your line filter is bad.

LTG : )

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Prevent electrical surges. When shorted/bad, they blow fuses.

Might not be your issue, but it is where I would start.

LTG : )

Just in case...

My Addams Family has a sticker that says to use an 8 Amp fuse where you said you were using a 5 Amp...

It wouldn't surprise me if some technician in the past had put in a 5 Amp fuse that you removed and replaced with a 5 Amp.

MDL 8A 250V is the recommended fuse, but make sure if it isn't MDL, you get a SLO-BLO fuse, not a fast blow.

Now, if the 8A fuse blows, you will have to figure out where you have too much power drain, and it could be right where other people were telling you to look, but put the correct fuse in first.

Unless it's 220v area. Then would be 5a SB.

The manual (page 1-47) says 4a SB for foreign territories.

Should the value of the fuse even matter if the backbox electronics are unplugged? The only current draw should be the filter caps (as per Lloyd's suggestion), the line filter, or a short in the windings of the transformer. Since the latter two are less likely, starting with the filter caps makes the most sense. After that, I'd go ahead and disconnect the line filter (since it's easier than diagnosing/replacing the transformer).