On Thu, 01 Jul 2010 22:20:16 +0000, Cydrome Leader ǝʇoɹʍ:

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.

The whole heatpipe/heat sink/mosfet mount block assembly on my SCS
350x350 WRMS rackmount amp probably weighs 2 pounds minus the 12 fets.
The actual heat sink looks like a round bristled aluminum brush through
which an infinitely speed controlled fan blows through from back to
front. SCS is not in business now, hasn't been for a long time but I
really like this amp. Low THD for a pro audio amp easily usable for a big
home system. Makes no noise unless you're pushing it then the noise
doesn't really matter.