vco7c thermal results

[Magnus Danielson]

>>>>> "t" == tomg  <vco at mindspring.com> writes:

 t> I did a few experiments for the fun of it. I set the vco at 440hz then
 t> sprayed freeze on the 3046 for 1 sec. freq went up to 582hz . It took it
 t> about 60secs to recover to 440hz then after a little minor drifting
 t> stabilizing at 440hz in about 3mins. Then I took my 45w iron and placed it
 t> in the middle of the 3046 for 30secs. The freq went down to 382hz again it
 t> took it about 60secs to recover to 440hz stabilizing in about 3mins. So I
 t> got out the hair dryer full bore and max heat about 6" from the board for
 t> 30secs freq went down to 332hz and took about 5mins to fully recover.

Now, talking about spray freezing... a very dear friend of mine got
the experience that instead of "discovering" errors by spray-freezing
components (like possibly wacko EPROMs) he actually introduces new
errors. So, excess use for the spray can may be a good way to actually
kill a good chip. This is due to the thermical changes of physical
size and now that you only got a chip shrinked in one end you get a
lot of nice physical stress, which can develope small cracks and
dislocations. This can also happend to a transistor when you zap it
slightly, you get a "beta-degradation". In the transistor case it
migth be cured by heating it up under certain conditions, but it is
not recommended to do such things.

Cheers,
Magnus