McCormack DNA-1 rear fuse won't stay in

I have a McCormack DNA-1 that I purchased new 20 some odd years ago. It is in my condo which I only live in during the week. Everything was fine when I left on Friday but today I come home to find that it won't power up. First I check the rear fuse and it seems fine but it won't latch back into place. I have looked at the fuse holder and don't see how it latches back in - usually you depress and turn it and something rotates under something else to hold it in place but I don't see anything like that on this fuse holder. Has anyone else experienced this issue? Does it need a new fuse holder?

Thanks in advance,

Bob Martin