Repair methods (was Cromemco 3101/Beehive B150 score)

[dwight elvey]

>From: "Andy Holt" <andyh at andyh-rayleigh.freeserve.co.uk>
>
>Tony wrote:
> > I haev never understood how you can understand digitial electronics
> > properly and not understand analogue electronics. I certaimly couldn't
> > understnad digital stuff until I understood things like transmision
> > lines, termination, etc.
>You can understand it well enough to use for many practical purposes by 
>just
>knowing a few "rules of thumb"*. A better, but still not necessarily
>detailed, understanding of the analogue background can help considerably in
>some of the more tricky situations - especially if you are
>"stretching"/abusing the "rules".
---snip---
Hi
Still, Tony has a point. In order to do intellegent trouble shooting, one
has to be able to understand how the analog elements of real circuits
effect how a circuit will function incorrectly. Sure, one can hunt and
swap parts until it works but to know the part you are unsoldering is the
cause requires true understanding of what that part is failing to do
from an analog sense.
Of course, one is hopelessly lost fixing power supplies without some
analog knowledge. Understanding feedback and how each part effects
the other is the key to fixing these parts. I see so many times that
some fellow will say, I've replaced all the capacitors and it still doesn't
work. They ask for help but I often don't know where to start. Should
I begin with elementary electronics or just use them as a remote VOM and
oscilloscope.
Dwight