An ounce of prevention is worth a pound of cure.

the_nines

AK Subscriber
Subscriber
Thought I would share what I did to prevent a major head-ache and possible disaster.

A couple of weeks back when I was removing the under-side of my 500B so I can clean the pots and switches, one of these suckers became undone and fell into the unit.

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After cleaning the pots and switches, I put back the under-side, placed the four bolts back in their place, fastened them.

I turn the unit over so I can place it back in its cabinet and I hear a "cling cling" noise. After investigating the source of the noise, I discover one of those suckers had become dis-lodged and fell into the unit. I think they are glued onto the bottom platform.

To avoid any possible damage (short-circuit) this loose piece can cause, I took a precautionary measure and taped it with electrical tape to the underside. After taping, I used a sharp and pointy object to insert a hole into the tape so that when the bolts are placed back they won't find any restriction and thread right through:

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Thought I would share an easy way to possibly avoid a disaster.

Thanks for considering.

Cheers. :)
 
Those are referred to as 'press-fit captive nuts'. They have a cross-hatched bit which is very slightly larger in diameter than the holes drilled in the bottom plate. You use a vise or other crushing implement to press the nuts into the holes where they are a friction-fit. You can buy replacements from McMaster-Carr (albeit in a slightly larger diameter, so you have to hog out the holes a bit). I had to replace one on the bottom of my KX-90.

If you are so inclined, you can also put a dab of epoxy on the cross-hatched section to provide even more binding to the casework.

-D
 
I've gone so far as to solder the perimeter of the captive nut to the panel. Need a BIG Iron for that tho. Epoxy on the inner perimeter sounds like a good bet.

Larry
 
Yup....

I hear both of you.

But I must admit (as perhaps you both will agree)..

A bit of electrical tape can't hurt.

Was this a design flaw on the part of Fisher?

Sure sucks as far as I am concerned.
 
Yup....

I hear both of you.

But I must admit (as perhaps you both will agree)..

A bit of electrical tape can't hurt.

Was this a design flaw on the part of Fisher?

Sure sucks as far as I am concerned.

I wouldn't say design flaw. More like a specific part (press-fit nut) outliving it's rated lifespan. On the other hand, close to 50 years isn't shabby!

-D
 
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