Re: UD3 ROM on a 3032

From: Gerrit Heitsch <>
Date: Sun, 30 Oct 2016 19:23:21 +0100
Message-ID: <>
On 10/30/2016 06:59 PM, Francesco Messineo wrote:
> On Sun, Oct 30, 2016 at 6:50 PM, Gerrit Heitsch
> <> wrote:
>> On 10/30/2016 06:20 PM, Francesco Messineo wrote:
>>> Hi all,
>>> I started working on my 3032 (2001-32), it will be a long project,
>>> since it's mostly a pile of dirt and rust (I've found it in this state
>>> 15 years ago, in a side of the street).
>>> I've seen the UD3 ROM socket populated, here's a picture:
>>> I'll be reading the EPROM in the next days, does someone have an idea
>>> about what might that be anyway?
>> When dumping the EPROM, please dump it twice, once normal and once with a
>> 1N4148 between Vcc of the EPROM and Vcc. Then compare the 2 dumps. If they
>> are the same, you can consider it a successful dump. If not, the dump taken
>> with the 1N4148 might be correct.
> I can tell my programmer to use a specific Vcc, I have to see what are
> the limits since I've never played too much with it in the past.
> Are you suggesting to use 5V and 4.3V or 6V and 5.3V?

5V and 4.3V. If an EPROM starts to lose data, it helps to lower Vcc. Why 
becomes obvious once you understand how and EPROM cell works.


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Received on 2016-10-30 19:00:02

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