[sdiy] TR-909 reset pin on PSU

[epk]

Great!  Thanks for the explanation!

epk

On Jul 9, 2009, at 4:24 PM, Colin f wrote:

>
> This pin holds the 909 CPU in reset until the power supply is  
> stable after
> power-on, and resets it again as the power goes off, or there is a  
> supply
> brown-out.
> It's there to stop the 909 writing spurious data into its battery  
> backed
> storage.
> There are various CPU reset control chips you could get that would  
> do the
> same job for any given PSU.
>
> Cheers,
> Colin f
>
>> -----Original Message-----
>> From: synth-diy-bounces at dropmix.xs4all.nl
>> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of epk
>> Sent: 10 July 2009 00:12
>> To: synth-diy at dropmix.xs4all.nl
>> Subject: [sdiy] TR-909 reset pin on PSU
>>
>> Hey all,
>>
>> I've got a TR-909 that I'm migrating to a custom case/panel and
>> external PSU.  The 909 has a reset pin on the PSU board that goes to
>> the switch board which is throwing me for a loop.  I don't really
>> understand what happens with this pin, and more importantly how to
>> spoof the functionality with an external PSU that doesn't have a
>> reset.  Is there an easy way to do this?
>>
>> Here's a pic of the PSU board schematic:
>>
>> http://i72.photobucket.com/albums/i182/wholetone/909%20psu%20board/
>> Picture2.png
>>
>> tx,
>>
>> epk
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>
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