Re: Fat40 RAM problem?

From: Istvan Hegedus <>
Date: Mon, 1 Sep 2014 14:29:00 +0200
Message-ID: <>

Just a quick question regarding the scope picture. I am new to oscilloscopes 
and have one Gwinstek, similar to this Rigol.
I can measure periodic signals well but have problems setting triggering for 
these logical signals.
How do you set trigger so that you can capture a certain event on these 
digital lines?

From: "A. Fachat" <>
Sent: Friday, August 29, 2014 12:53 AM
To: <>
Subject: Fat40 RAM problem?

> Hi there,
> I've analyzed the RAM problem on my Fat40 a bit more. I've recorded the 
> broken
> addresses - which are stable - and measured the RAM chip in question 
> (UA16 )
> with the scope.
> See
> What looks interesting is that the data I/O pins of the RAM even stays 
> high
> when I write a zero into it! I.e. either the RAM is broken and pulls the 
> line
> high, or the driver (or something else) is broken. However, I cannot see 
> why
> the combination of address bits should create a driver failure. Measuring
> another chip in the same bank shows the corresponding data line going low 
> as
> it should, as well as the same chip with another address.
> Anyway, I've ordered a 4116 RAM replacement and will replace the chip to 
> see
> how it works out.
> André
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Received on 2014-09-01 13:00:03

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