The Museum of HP Calculators

HP Forum Archive 20

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HP 9100A/B Transistors
Message #1 Posted by Richard Wilder on 5 Nov 2011, 11:12 a.m.

Anyone know the significance of the colored paint dabs on many of the transistors in these calculators? Maybe they were hand selected for parameters to work in the particular circuit(?)

      
Re: HP 9100A/B Transistors
Message #2 Posted by Joel Setton (France) on 11 Nov 2011, 9:08 a.m.,
in response to message #1 by Richard Wilder

Richard,
The HP Journal article on the 9100 mentioned that the transistors were burned-in, to detect early failures and improve reliability. As far as I know, this is not related to select a particular parameter.
I hope this helps!
Joel


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