On ETSY there were 24 pieces of the MPS3639 for a very reasonable price. They sold a few hours ago, so Christian may have found what he was looking for.
On Mon, Oct 27, 2025 at 6:33 PM Christian Corti via cctalk < [email protected]> 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. > > Does it mean that a failing PDP-8 will stay a dead PDP-8 from now on? > > Christian > >
