[sdiy] Repairability of modern analog synths

[Roman Sowa]

I've had one damaged microcontroller once. Can't remember the synth, but 
the damage was very tricky, and for some users could be even "I can live 
with that" type of fault. It was working, everything was fine, except 
pitchbend. I also thought "it's never the microcontroller" and searched 
for possible damage on the way. It quickly turned out that one 
microcontroller pin was used to detect the polarity of pitchbend wheel, 
and that pin was dead. You couldn't force it to the other state. Maybe 
some nasty ESD event from 30 years ago in the factory or simply bad 
luck. After micro replacement it worked as new.

And that's not yet the strangest fault I've seen in a synth.

Roman

W dniu 2020-10-20 o 15:03, Gordonjcp pisze:
> On Mon, Oct 19, 2020 at 03:42:34PM -0700, David G Dixon wrote:
>> It would seem to me that one big problem with "modern" synths is replacing
>> programmed chips.  I can't speak for other people, but when I open up a
>> broken synth and see microcontrollers, I close it back up and leave it where
>> I found it.
> 
> Why?  It's never the microcontroller.
> 
> That's like all the crappy garages that used to go "oooooh, can't fix that, it's got a computer, it'll be the computer that's faulty, that's expensive and needs dealer tools".  Does it hell, it needs a set of tyres put on, you lazy tit.
> 
> If you see a modernish synth with a fault, it's going to be the power supply or one of the much-maligned 405x MUXes.  The closest I've got to a faulty microcontroller in a synth is doing the DSP in MS2000s - funny I've never seen a Microkorg with a dead DSP!
>