On Sunday, February 28, 2021 at 3:07:06 PM UTC-5, wrote:
wrote:
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The only time I really remember transistors being a red flag (other than early Germaniums) were some small Hitachi signal transistors from the 70s-80s - the TO-92 ones with the beveled top. Those things would go leaky or open or intermittent (their choice). It got to the point back then that I just automatically changed them whenever I saw one in anything I worked on.
** You talking about the the dreaded " black leg corrosion" problem ?
TO92s and the like with silver plated leads.

Silver sulphide would form on the plating, travel into the device and eat the chip.

Always Jap stuff like Marantz.

..... Phil

Yep. I think Chuck one post up identified the number.