[sdiy] 8080-based synth reliability

[Dave Leith]

Plastic, ceramic case or ?

On Fri, Oct 6, 2017 at 4:39 PM, Frédéric (Opensource) <marzacdev at gmail.com>
wrote:

> Hi Dave.
>
> Any idea why the 8080 died?
>
> Fred
>
>
> Le 06/10/2017 à 22:52, Michael Zacherl a écrit :
>
>> On 6 Oct 2017, at 22:07, Ove Ridé <nitro2k01 at gmail.com> wrote:
>>>
>>> You ought to document the project for posterity and 5 minutes of
>>> Hackaday fame. If you post a ROM dump or perhaps source code if it survived
>>> for all these years, the project might take on a modern life on its own by
>>> dedicated hackers. (I for one wouldn't mind looking at it.)
>>>
>> Oh boy, I love this kind of synchronicity!
>> The other day I dug up my old original MPF-1 to show the students:
>>
>> https://en.wikipedia.org/wiki/Micro-Professor_MPF-I#/media/File:Mpf-I.jpg
>>
>> Dave, your posting definitely brings back old memories! :)
>> Very inspiring!
>>
>> m.
>>
>> On Friday, 6 October 2017, Dave Brown <davebr at modularsynthesis.com>
>>> wrote:
>>> This is definitely DIY related and somewhat synth related in that it is
>>> a digital 3 voice synthesizer.  In late 1976 I designed a dedicated 8080
>>> based three voice PWM synthesizer as a doorbell.  The code was based on a
>>> program called Music for the Processor Technology Sol-20 computer.  I had
>>> to disassemble the program to get it to run on a basic 8080 system using a
>>> single 2708 EPROM and two 2114 static rams.  It used a simple transistor
>>> driver for the speaker.  The 8080 is unmarked so I think it might even be
>>> an engineering sample.
>>>
>>> This system has continuously run for approximately 14,870 days or nearly
>>> 356,880 hours.  Well this week it died.  The processor is just absolutely
>>> lifeless.  I had another 8080 from the same vintage but at least marked and
>>> replacing it brought the system back to life.  Note that in the 40 years
>>> the 2708 has not forgotten even though the guaranteed retention is only 10
>>> years.  I think it will outlive me.
>>>
>>> It was a really progressive program for the time.  This doorbell also
>>> includes a RS-232 interface so I could compile new music to upload to it
>>> for special occasions.
>>>
>>> Dave
>>>
>> --
>> http://mz.klingt.org
>>
>>
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