On Wed, 01 Sep 2010 23:39:30 -0500, William R. Walsh wrote:

A follow up to my follow up...one thing that I've noticed is how hot the
various "Computer Drive" receivers run even when operating normally. So
I found my IR non-contact thermometer and had a look at the newly
repaired SA-310.

At idle for around 20 minutes, the temperature of the heatsink had risen
to 130 degrees Fahrenheit (54 degrees Celsius)! And the unit was just
*idling*. The hybrid's internals are probably a good ten degrees hotter
still. Call me picky, but that is not what I'd call the recipe for
semiconductor longevity! Ouch! (Just how did the last hybrid--presumably
the original--manage to live so long?)

By comparison, the Class AB SA-120 (with its identical power rating)
idles around 88-90 degrees F after being on for a while. Its STK module
also has a much smaller heatsink.

For now I have made a "contraption" consisting of a DC muffin fan
affixed to the bottom of the SA-310 using bubble wrap on the corners to
stop the case from vibrating. With this setup, and two books at each end
of the receiver to give the fan clearance, the temperature never gets
above 105 degrees F even with the cover on. Most areas of the heatsink
are slightly cooler than that (in the high 80s or lower-middle 90s).

Later, when I get some free time, I plan to install two small fans on
the heatsink, helping to pull air over it and hopefully keep that hybrid
alive and comfortable.

It has been suggested that minorly violent and mostly non-destructive
disassembly of an STK-series hybrid amplifier is possible. Some people
even make the claim of having repaired the bad parts within. I may just
have to try it if the old hybrid hasn't walked off yet.

The DC offset as measured at the speaker terminals (no source playing,
no speakers attached of course) is between 8-12mV for both channels now.
I believe the unit to be fixed. :-)

William

Do you have the temp specs of the replacement STK?



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Live Fast, Die Young and Leave a Pretty Corpse