Mark wrote:
The mainframe power transistors are NOT darlingtons. They are plain NPN/PNP power transistors with non-standard pinouts.
The TO-127 pinout is ECB -- most other plastic power transistor packages are BCE.
I just pulled the cover off a TM503, and the 151-0349-00 (and 151-0373-00) devices in it are NOT darlingtons.
At least some Tek manuals say the 151-0349-00 devices are SJE924s, and the information I have on those (which I copied from a now long lost Motorola databook of the era) indicates that they are darlingtons (there is some corroboration for this on the web, but I have not found a web datasheet). However, a current source of Tek parts (see below) says that its 151-0349-00 devices are MJE2801s, which I believe are not darlingtons. So, either Tek was incorrect in stating that P/N 151-0349-00 = SJE924, or the Motorola datasheet I copied from was wrong that SJE924s are darlingtons, or I copied wrong. (Surely it couldn't be the third? ;-) In any case, it does not appear that the transistors in TM5xx frames are darlingtons.
If anyone wants original form factor TO-127 transistors (presumably Tek old stock, marked "034900"), they are available from:
http://www.sphere.bc.ca/test/tek-parts/tekparts2.html Best regards, Charles _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
