Resurrecting integrated circuits by cooking them.

[Jeffrey S. Worley]

Yesterday evening, in the process of refurbishing five very badly
treated Atari 800 computers I had a hunch and subjected a failed Pokey
chip (Atari Part CO12294 Wikki link https://en.wikipedia.org/wiki/POKEY
    ) to high heat by way of the barrel of my soldering iron until
saliva evaporated from it in about 1 second.

The chip, which did not work before in any of the machines now works
perfectly.

Pokey (see wikki link) is common to all Atari 8-bit computers and
common in many Atari coinop video game systems.  These chips are
becoming scarce, so much so there is a sort of replacement being
manufactured 
https://hotrodarcade.com/products/pokeyone-atari-pokey-chip-replacement-for-atari-arcade-games
.

The replacement Pokey only emulates the audio portion of the original
chip, leaving the PotKEY part unimplemented.  Pokey gets its name from
Potentiometer Keyboard.  It also handles the Atari SIO peripheral
signals, so without those an Atari computer cannot use standard
peripherals like serial disk drives, and other common interfaces. 
Thus, for Atari computers a true Pokey is a must.

I stumbled upon a fix for this one and wonder if I reinvented the wheel
or if this information may be of use to the group in treating other
sorts of chips.

Reflowing is a treatment for a lot of hardware these days and generally
regarded as a hack which won't last.  As modern hardware, CPU's and
video chips in particular run very hot, I can see how this might be,
but Pokey and most of the stuff we work with don't have this
environmental restriction.  Most of our gear runs at 40 degrees
centigrade or lower.  So I'm guessing the problem with my disused chip
was oxidation within the package and that cooking the chip a bit
cleaned things up?  Any advise or observations would be appreciated.

I tried this on another chip the same evening, an Antic.  The Antic DID
work for a second or two, whereas it had before given no signs of life,
but then returned to its failed state.

Best,

Jeff
(Technoid Mutant)