Your Kyocera R-451 receiver overheats? here's one reason

[wualta]

Could be as simple as a loose insulator sheet.

I don't see this in the 651 or 851, but in the 451 there's a stiff sheet of frosted Mylar slipped in between the bottom of the mobo (ie, the main PCB), and the metal floor of the case, and glued down. In my 451, the glue had dried out and this sheet had come loose and was covering the lower vents of the heat-pipe section of the heat sink, thus making convection cooling a difficult proposition.

Owners of the 461 might want to flip theirs over and have a look, just in case.

 

[chasaboo]

Thank you for posting.

I had read about Kyoceras getting hot and made sure I checked it out when I bought mine. I actually spoke with the seller for about 45 minutes.kind of stalling as the Kyocera played to see if it would get excessively hot.

I wound up buying the R-461 as it looked great, sounds amazing and had no over heating issues at all.

Will keep an eye out for that problem though.

 

[wualta]

Excellent. My 451 is a 1985 model, so it's not even that much older than the typical 461, so the adhesive that held this sheet in place could easily be in jeopardy inside a unit made in, say, '87. Even though the 461 uses BJT output transistors (which generally run cooler than early MOSFETs), blocking the ventilation slots is still a no-no.

I was lucky that I just happened to flip mine over, otherwise I'd probably be wondering why my new toy was trying to bake itself.

One other discovery to watch out for: The knobs are actually metal shells slipped over plastic knobs and glued in place. No surprise, this glue is also drying out and the shells are loose on my R-451. Just a heads up.