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-   -   What is this blue paint on old TO-92 Motorola parts?? (http://www.diyaudio.com/forums/solid-state/226665-what-blue-paint-old-92-motorola-parts.html)

BenY 30th December 2012 05:14 AM

What is this blue paint on old TO-92 Motorola parts??
 
1 Attachment(s)
Is it a relabled or a fake part?
Any one knows the answer..?
Thanks.

freax 30th December 2012 05:58 AM

I have seen this color of transistor before, I don't think they are fake.

http://www.mail-archive.com/chipdir-.../msg02157.html

Seems to be that they are matched types, or high tolerance/spec types.

Quote:

High Jens,
I haven't found a trace of BF311 in my database, numbers start with
BF316.
Regarding the blue paint, all I can tell you is, that I have some
old Tektronix oscilloscope boards, which are full of rare marked
transistors, blue painted Motorola signed, but numbers you will
never find anywhere. Seem common stuff.
I guess those are selected and tested items, but who would know.
Don't take this as fact though, its just somebody elses conjecture.

Andrew Eckhardt 30th December 2012 06:20 AM

I can at least say for sure Motorola did indeed paint their parts like that over a decade ago (maybe 2)... back when someone may have cared about unaided eye component identification.

Ian Finch 30th December 2012 01:44 PM

Yes, Philips did the same with their TO92 parts. When laser marking was introduced, clearer results were obtained by burning away the paint, giving dark blue or black lettering on a light (silver-blue) body. I don't think that had anything to do with quality levels - other than to identify their S.E. Asian production.

john curl 30th December 2012 02:34 PM

I've got 100's of them and they are not fakes.

BenY 31st December 2012 12:45 PM

In other words..

These are the standard type BJT`s of their time, nothing special about the metalic blue color marking.

Thank you all..


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