<From CLASSICCMP-owner(a)u.washington.edu Wed Apr 14 21:46:30 1999 <Return-Path: &lt;CLASSICCMP-owner(a)u.washington.edu&gt; <Received: from lists2.u.washington.edu by world.std.com (TheWorld/Spike-2.0 < id AA01313; Wed, 14 Apr 1999 21:46:27 -0400 <Received: from host (server(a)lists.u.washington.edu [140.142.56.13]) < by lists2.u.washington.edu (8.9.3+UW99.02/8.9.3+UW99.01) with SMTP id SAA1 < Wed, 14 Apr 1999 18:46:23 -0700 <Received: from mxu1.u.washington.edu (mxu1.u.washington.edu [140.142.32.8] < by lists.u.washington.edu (8.9.3+UW99.02/8.9.3+UW99.01) with ESMTP id SAA2 < for &lt;classiccmp(a)lists.u.washington.edu&gt;du>; Wed, 14 Apr 1999 18:46:16 -0700 <Received: from tele-post-20.mail.demon.net (tele-post-20.mail.demon.net [19 <Indeed you have... In fact, IMHO, everyone here who does design, or <serious logic troubleshooting/repair should consider this instrument. Yes <it's expensive (\pounds 550+tax in the UK). But I think it's well worth it Well I don't have to have it... I have a 16 channel analyser good to 20mhz and two 0'scopes and a custom anlyser hack I did years ago. Generally if I have to bring out the scope it's nasty. The 8f was trouble shot with nothing more than my fluke 12 multimeter as it ws closest at hand. <Even an LED and a resistor (between an IC pin and ground) is a good <start. No you won't see fast pulses. But you will see things that are <stuck it totally the wrong state. I debugged my first homebrew <microcomputer (SC/MP + RAM, basically) using just such an LED+resistor I have one in a clear pen barrel with a point and and a cliplead, very handy! It's pretty easy to tell, high low and something that's pulsing even at high rates. Another handy item is a 4040 cmos counter to make fast things into tones (earphone). That trick came from the NS* disck controller troubleshooting hints. Intelligently used simple tools can be very useful. Allison