27 Oct
2025
27 Oct
'25
8:32 a.m.
On 10/27/25 05:26, Christian Corti via cctalk wrote:
It seems that nowadays you can't get *any*
replacement for
failing DEC 3639 aka 2N3639 transistors. All parts are
obsolete and unobtanium, e.g. 2N3640, PN3640, MMBT3640 and
so on.
So, what can be used instead? The most important
electrical parameter is the storage time. It needs to be
*very* low, around 20-30 ns.
Oh, it apparently is Silicon. So, an MPSH81 should really
do well.
Jon