[sdiy] TB-303 braindead

cheater00 . cheater00 at gmail.com
Wed Jun 17 11:32:08 CEST 2015

The battery wire is right, I checked photos of other people's 303 pcb,
and besides I remember myself.

The same behaviour happens with a 9V positive-outside wall wart.

However i did have to re-solder a bridge I made years ago because of a
lifted track. That bridge is connected to one of the CPU's pins. Maybe
something else messed up around it as well.

Robin: how do I use pin 7 to reset the CPU? Can I just apply a voltage
I source from somewhere else on the PCB?


On Wed, Jun 17, 2015 at 11:22 AM, Rob Spencer <Rob at gmsn.co.uk> wrote:
> The best advice I every got and has been proving right in 99.999% of any fault finding I've done on mechanical, electronic and IT systems is that if something has recently changed then whether you understand it out not that is the cause of the issue :)
> I would check the schematics to make sure the battery wire has gone back on the right place.
> Cheers
> Rob
>> On 17 Jun 2015, at 10:02, Carlos Portela <carlosrochaportela at gmail.com> wrote:
>> Wrong polarity?
>>> On 17 Jun 2015, at 10:42, cheater00 . <cheater00 at gmail.com> wrote:
>>> Hi guys,
>>> upon replacing the battery wire which broke off in my TB-303, I have
>>> found it to be relatively braindead. It will play some sorta random
>>> patterns when in either song or pattern write mode - which it starts
>>> doing right when turned on. The pattern buttons sometimes change the
>>> pattern, but you can press the same button a few times to get a
>>> different one. A/B obviously doesn't do the right thing either but
>>> changes the pattern as well. Nearly all LEDs are lit up but some are
>>> much brighter. When in either play mode, the same LEDs are on but
>>> pressing the start button turns them off. You can't get it to play
>>> patterns this way. I was wondering if anyone knew what might be wrong
>>> with it.
>>> Cheers
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