Return-Path: robot-board@oberon.com Received: by media.mit.edu (5.57/DA1.0.4.amt) id AA23966; Mon, 10 Jan 94 15:15:47 -0500 Received: from ([127.0.0.1]) by oberon.com (4.1/SMI-4.1_Armado.MX) id AA22393; Mon, 10 Jan 94 15:02:43 EST Date: Mon, 10 Jan 94 15:02:43 EST Message-Id: <199401102001.PAA01469@glendower> Errors-To: gkulosa@oberon.com Reply-To: gkulosa@oberon.com Originator: robot-board@oberon.com Sender: gkulosa@oberon.com Precedence: bulk From: Greg Kulosa To: Multiple recipients of list Subject: Re: Power-to-Ground Short X-Listprocessor-Version: 6.0b -- ListProcessor by Anastasios Kotsikonas > > > > OK, this is embarrassing, but I appear to have an elusive > power-to-ground short on my microprocessor board. I am assembling the > 6.270 version 2.11 board and it failed the continuity check between > ground and the cathode of D1. Neither I nor anyone else who has looked > at it can find a visible soldering error. I have lately been reduced to > tracing the circuit layout in appendix C and removing components that > bridge the power and ground areas of the board in order to find the > offending component. So far I have removed: > > D1, VR1, C4,7,12,&13, and R8. > > Does anyone have any ideas or suggestions I might try before I > end up desoldering my entire board? Please email me! Yes, there was a message sent out right after I sent out the Rev 2.11 boards. Paul Malenfant discovered that there was a mistake made when they made the boards. There is a hole that is plated through on the main board that is not supposed to be. It touches both the ground plane and the 5V plane. If you hold the component side up with the power switch in the lower left corner, then the hole is on the right side of the board, halfway up, near Capacitor C4. You need to use either a small drill bit to remove the plating, or an x-acto knife. Be careful, because there are some small traces nearby. If you need more info/help, send me personal E-mail. > Dennis Burke > dburke@farad.elee.calpoly.edu -- Greg A. Kulosa | "If we are to be damned, let's be damned for what Systems Administrator | we really are" - Jean-Luc Picard Oberon Software |___________________________________________________ gkulosa@oberon.com One Cambridge Center, Cambridge, MA 02142