[sdiy] 8080-based synth reliability

[Ove Ridé]

I plead guilty as charged!

On Friday, 6 October 2017, Rick Jansen <rick.jansen at xs4all.nl> wrote:

> Nerd! :-)
>
> On 6 Oct 2017, at 22:07, Ove Ridé <nitro2k01 at gmail.com
> <javascript:_e(%7B%7D,'cvml','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.)
>
> On Friday, 6 October 2017, Dave Brown <davebr at modularsynthesis.com
> <javascript:_e(%7B%7D,'cvml','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
>>
>>
>>
>> David J. Brown
>>
>> Modular Synthesis, LLC
>>
>> http://modularsynthesis.com
>>
>>
>>
>>
>>
>
>
> --
> /Ove
>
> Blog: <http://blog.gg8.se/>
>
> "Here is Evergreen City. Evergreen is the color of green forever."
>
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>

-- 
/Ove

Blog: <http://blog.gg8.se/>

"Here is Evergreen City. Evergreen is the color of green forever."
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