Path: utzoo!utgpu!news-server.csri.toronto.edu!qucdn!leek
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Problems with LUCAS&FRANCES (was 2.0 in FRANCES)
Organization: Queen's University at Kingston
Date: Sunday, 16 Sep 1990 12:35:34 EDT
From: <LEEK@QUCDN.QueensU.CA>
Message-ID: <90259.123534LEEK@QUCDN.BITNET>
References:  <449417@neabbs.UUCP>

In article <449417@neabbs.UUCP>, joost@neabbs.UUCP (JOOST BOERHOUT) says:
>
>I looked at the power and ground lines of the 74ls245 drivers using a
>20 MHz scoop. This showed a lot of high frequency junk going on
>(peaks of 1 Volt !) which seemed to be related to the /DATABUSEN signal.
>There is no way I can get rid of these peaks (I use 1uF tant parallel
>to 100n ceramic for decouple caps).
>
A got about 20mV DC volt difference between the 74LS245's and the power
supply ground.  I put in pieces of wire (about 22 AWG) to ground the 245's
directly to the power supply connector and changed the bypass capacitors
to 0.47uF monolithic.  I don't have a scope, so I don't know what kind of
noise I am dealing with.  Right now the 245 GNDs vs power supply GND reads
0.5mV DC on my digital voltmeter,  so I would assume the grounding is good.    t
Hope this works for you.

>
>- joost -

K. C. Lee
Elec. Eng. Grad. Student