Resurrecting integrated circuits by cooking them.

[William Sudbrink]

Brent Hilpert wrote:

On 2019-Jul-24, at 10:31 AM, Jeffrey S. Worley via cctalk wrote:

>> 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.
>
> cross your fingers that it stays working. I performed a fix like this some
> years ago with a ca.1970 chip from an SSI logic family from Sony. However,
> it reverted to its failed state some weeks or months after the heat
> application, long after (obviously) the chip had returned to ambient
> temperature. So it wasn't merely that the chip was temperature sensitive,
> the heat application indeed must have had made some internal alteration,
> but it wasn't permanent.

Probably temporarily reattached a bond wire which "re-broke" after a few
thermal cycles.

Bill S.



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