On Thu, 02 Sep 2010 12:36:01 -0700, William R. Walsh wrote:

Hi!

A PDF at alldatasheet.com shows a 2040 as having a max junction temp of
150 C. That's 302 F. I would guess most are the same.

I don't think the module would live very long at that temperature. The
behavior of Computer Drive seems to keep it hot, too. I've always been
of the school of thought that said "keep your silicon devices cool and
they will live longer".

Then again, I have no reason to believe that the old module was ever
replaced, and it did survive 27 years worth of usage...

I don't know about the relative toughness of STK-XXXX amplifier modules.
I've always been of the impression that they are not always robust. Yet
it seems that people have abused them and gotten away with it. And
outside of this one receiver, I've never lost one...

William

I've always thought the PCDPP to be robust. Your right they wouldn't last
too long at a max Jt of 150C but most survive well at a working temp of
105C.

Panasonic, Sanyo, Sansui, Pioneer Yamaha etc used them. Rear Projection
TV sets used them for convergence amps which I consider the hardest
working part of the set. So there must be some reason these were chosen
other than a convenient package. If you use the correct amount of heat
sink compound spread evenly and torque them down properly provided the
heat sink has enough surface area there is no reason for these to be
problematic. Like you said the originals in your SA lasted 27 years even
biased class A.



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