Hi --
I have recently purchased several hundred TO-3 transistors from a well known parts dealer. I prefer not to give their name right now pending resolution to this issue...
I noticed these transistors were very nice looking, clean NOS Motorola's and thought nothing of them for awhile. In fact, I have already gone thru 200 of them.... Tonight - I noticed variations in package (tooling, etc) as well as differences in insulation around transistor leads. Normally - I would think nothing of this either. BUT -- all these transistors have the exact same date code -- 0223. And - didn't Motorola change over to On Semiconductor in 1999? Counterfeits?!?! Aw d@mn!!!!
The parts seem to work well in a simple, low current power supply. Pretty much any similar NPN transistor would work. However, this is in a relatively high voltage supply -- 160 to 240VDC. Part may be good for gain and current but could still be rated for max of 60 volts of some awful low value. These parts work but I don't want a ticking time bomb by using voltages 4x what the parts are rated for....
Is there a way I can find out what these transistors really are? If you pop the top - do any transistors have part marking internally on the die itself (i.e. etched in the corner)?
-- Ed