[sdiy] Repairability of modern analog synths

[Nathan Trites]

David - learning the ins and outs of poly synths is where I really came to
love Chamberlain's Musical Applications of Microprocessors. Between that
book and studying schematics for more basic polys (Prophet, Polysix, etc)
from the early 80s you can get a good idea of how to troubleshoot
architecture like that. From there narrowing down issues as global vs per
voice, then figuring out the control signals for broken features, or
identifying the chips in common across multiple issues. I found this
daunting for the longest time but now I love it. IMO the hardest part is
navigating the denser PCB layouts. A few things here also collected dust
for years before that development happened though :)

Back on thread:
Modern consumer gear is just not designed to be opened/repaired compared to
comparatively more expensive vintage gear that would have required regular
calibration/maintenance from the get go. Korg Minilogue is a nice example.
No reason to ever open one if it works, but just expensive enough that you
can't just throw it away when it breaks. It takes a dozen or so screws plus
removing a knob + nut for all 30+ pots in order to replace one of them.
It's totally repairable but damn does it take a lot of time to open and
close. Most other issues like repairing SMT are more a matter of having the
right tools or a steady hand for tight spaces.

Nathan

On Tue, Oct 20, 2020 at 12:00 PM David G Dixon <dixon at mail.ubc.ca> wrote:

> Well, I've got a broken JX-8P collecting dust behind my workbench in the
> garage.  My problem with broken digital synths isn't that I'll have to fix
> the microcontroller.  My problem is that I'm very scared to even start
> looking at it with a view to fixing it.  With analog gear, I'm generally
> pretty confident that I'll find the problem quickly, because I understand
> how it works.
>
> What I'm trying to say is, it's a ME thing, not really a DIGITAL thing.  As
> far as the "lazy mechanic" analogy, that would be true if I actually did
> this stuff for money, but since I only do it for shits and giggles, I don't
> think it really applies.  Life's too short to do stuff you don't enjoy.
>
>
> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of
> Gordonjcp
> Sent: Tuesday, October 20, 2020 6:04 AM
> To: synth-diy at synth-diy.org
> Subject: Re: [sdiy] Repairability of modern analog synths
>
> [CAUTION: Non-UBC Email]
>
> 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!
>
> --
> Gordonjcp
>
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