Trevor Wilson wrote:

"David Nebenzahl" wrote in message
.com...
On 7/1/2010 2:16 PM Trevor Wilson spake thus:

"Cydrome Leader" wrote in message
...

David Nebenzahl wrote:

Got someone with a Kyocera receiver (R-851, 85 w/chan.) that they say
"smells like something's burning". Don't have more specific information
than that; I'm assuming no magic smoke is visible. I'm advising them
that perhaps something (dust, etc.) is in the heat sink that's getting
heated and smelling. Apparently the output stages (MOSFET) of these
beasts tend to run on the hot side.

weird heatsink in that thing:

http://www.audiokarma.org/forums/sho...d.php?t=246095

**Ah, heat pipes. Quite common in the late 1970s, early 1980s. If the
fluid has leaked, there can be problems. A quick way to test is to power
up and ensure that heat travels rapidly (less than 10 seconds) from the
hot devices to the other end of the heat pipe. If it doesn't then it is
possible that the fluid is gone from inside the pipe.

Having been inside this unit before, I'm fairly certain the heat pipe is
intact.

**You need to measure to be certain.


Any idea what the fluid is?

**Not really. Some kind of refrigerant. It could be FreonT, ammonia, alcohol
or a number of others.

I got curious and dug up a sample of a heat pipe (Noren Products
http://www.norenproducts.com ) from a trade show, and it seems they can
even be filled with distilled water depending on the use.

It's still interesting to me that anybody bothered to use these in
amplifiers, products where nobody cares about size and complains about it
being made too sturdy and too heavy.

I have an ATI amp where it's not clear if the heatsinks or tranformer
weigh more.