Interesting 8/L problem (more than you want to know about

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sat Apr 5 16:58:00 2003

> So the object lesson here is that all switching transistors are
> not created equal, even in 1960's technology! Naturally since the

Having repaired (1960's) HP9100 calculators, I can agree with that. Some
of the transistors in there are critical. Very critical. The ROM address
drivers, for example (the main ROM is an inductive matrix...). And even
the EHT oscillator transistor is somewhat critical -- many of the obvious
choices for that one (like TV line output transistors -- HOTs to you)
will oscillate, but he voltage regulation loop doesn't work

-tony
Received on Sat Apr 05 2003 - 16:58:00 BST