Kits vs ready-made (was RE: Rebirth of IMSAI) - test-drb@ccmp.vtda.org

1 Apr 1999

This strategy is pretty popular with analog work being tried for the first
time.  I prefer to wire-wrap my digital stuff, and I've shown that wire-wrap
between digital and analog circuitry can be mde to work as well.  I prefer
my prototypes to be really rugged unless there's a specific reason why one
can't be, and I'm always afraid to play with those
"spiderweb-technology"
circuits, so once built, they never get any improvement from me.

Now, I've learned a few tricks from those analog weenies who use this kind
of stuff all the time.  I'll certainly never forget watching one guy track
down a 4MHz clock from a processor getting into the analog section of his
circuit by using a divider with points sharp enough to penetrate the solder
mask and a spectrum analyzer.  He found the section of ground plane which
needed bypass, then fixed it with a couple of capacitors bypassing the
unwanted signal to just the right place.  No mean trick if you ask me.

Dick
-----Original Message-----
From: Allison J Parent &lt;allisonp(a)world.std.com&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Thursday, April 01, 1999 7:24 PM
Subject: Re: Kits vs ready-made (was RE: Rebirth of IMSAI)

...
 <What I do if I can stand the stray capacitance (and
I often can) is take
<a piece of copperclad for the groundplane. I then stick (double-sided
<tape is strong enough) little 'islands' of stripboard, track side up onto
<the groundplane. Solder the ICs to the stripboard. Then solder the ground
<wires from the strips to the groundplane (as short as possible). That
<will anchor the stripboard in place. Decoupling caps go from the power
<strip straight to the groundplane, etc.

That happens to be an effective way to do it.  Works well for RF too.

As to proto, I have a few peices of equipment that were deliberately built
that way with over 15 years on them.  With a little care it can be very
rugged.

Allison