[sdiy] Korg Delta problem

Gordonjcp gordonjcp at gjcp.net
Tue Jun 19 01:31:44 CEST 2018

On Mon, Jun 18, 2018 at 05:56:27PM -0500, Pete Hartman wrote:
> I literally had spew from an SMD electro corrode and damage the PCB on a
> Roland XP-50.

I guess if it happens, it must be possible ;-)

> I had another synth where I couldn't get it to do anything until I replaced
> some mylar caps in the psu section.

I've never had mylar capacitors fail.  I've had masses of SMD ceramics
and disc ceramics fail, often when used for decoupling.  A stock fault
on a particular Kenwood radio I used to deal with a lot was that an
0.1μF 0403 ceramic would start to leak and screw up the mike preamp
biasing, causing fairly weird audio effects as the preamp went unstable.
Another model of Tait radio had them fail in the squelch level
comparator, so although the radio would appear to work okay on test the
squelch would never open when it was configured in trunking mode, and it
would never sign into the network.  They also had ridiculous problems
with dry joints, no doubt due to being mounted in vehicle cabs where
they were subjected to masses of heat and vibration.

I know for sure I've done a couple of thousand of each of those :-D

> Acknowledging that is NOT the same thing as "MUST RECAP EVERYTHING" shotgun
> "troublshooting".

Oh absolutely.  But I can't really think - clear PSU issues apart - of
something where I'd immediately wade in and start looking at capacitors.

As we all know, it's always the 4051 muxes... ;-)


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