Fuse corrosion

[Alex Eisenhut]

I found a ~1960s-era Grundig TK79U reel to reel tape machine while thrifting. Inside is a bit of a mystery, why is only one fuse corroded?
Like really just the fuse, the holder seems uninterested in whatever the fuse is doing.
And the other fuse is fine.
The machine is clean and dry, not even a musty smell.

[coppercone2]

I think that green is nickel. Maybe the fuse holder is tinned and the fuse is nickel plated.

That is just my guess, because the fuse holder is bendy, they don't like putting nickel on stuff that flexes alot, its stiff. Fuse holders deform alot when you insert a fuse compared to alot of other contact things.

But they do have nickel plated fuse blocks, so i don't know. You can get nickel plated brass or tin coated copper alloy commonly for fuse holders

[ebastler]

Where are those fuses in the circuit? Could it be the case that one of them sees AC, the other DC (or rectified AC)?

[factory]

This is a common issue with Grundig equipment of a certain age and some other makes from Europe, the corroded fuses & holders appear frequently on the UK vintage radio forum.
Dissimilar metal corrosion is a thing.

David

[Alex Eisenhut]

Yeah, must be different metal in the other fuse. Maybe consistency wasn't much of a thing back then.
The unit still runs, that's the funny part.
I guess I'll be joining a vintage radio forum soon!