jerrythek wrote:Paolo T. writes documentation for Korg Italy, and cares about the products and users. But sending him PM and emails is not the right answer.
The issues need to be run through the local Distributor and they will get things passed on to Korg Italy. Talking about crashes etc. doesn't really help to fix them - finding a known, repeatable operation or steps that will cause a crash makes it easier to find. And it seems to my innocent/early involvement with this that that has not been able to be found.
In the US we have had no incidents or reports of LED problems until this morning. Someone called in looking for me based on the activities here at the forums. So we will certainly look into it. As is Korg France (Algam) and Korg Italy. I have confirmed they are working together to explore this.
I'm sorry to see this has spiraled out of control for so long now, and to be honest, I currently have nothing significant to offer. Except my attention to the matter. Korg IS following up on this.
Regards,
Jerry
Hi Jerry,
The trouble with any intermittent hardware lockup is that it is not repeatable and stochastic. You cannot repeat it at will with a "formula" to make it happen. However it is disastrous when it does happen. Intermittent faults like these are normally caused by out of tolerance timing on digital signals connected to IC's resulting in a race condition or illegal input condition that locks the IC into an indeterminate state. It is a function of temperature and timing so it happens more when it is hot and when the keyboard is very busy.
What I said above is well known to any digital circuit designer (I am an electronics engineer).
I can tell you the following experience from everybody who has experienced the lock up (including me) ...
It happens during heavy activity, like during a live gig, normally when the keyboard is hot ...
a) Not one keyboard note or button works - the button scanning stops.
b) The LED multiplexing stops, so some LED's glow very bright and others that should be on do not illuminate.
c) The touch screen handling stops, no response to touch screen events
However the following continues to work leading me to believe there is no software or microprocessor or memory fault:
d) The display output continues to count beats
e) The style play section continues to play a style but you cannot change the chord
f) Any keyboard notes depressed at the time of the lock up continue to sound, they are"stuck on".
This should be enough diagnostic information to allow Korg hardware engineers to determine the common point of failure - presumably somewhere on the main board where all of the three peripheral boards with buttons, keys and LED's connect together via ribbon cables. My guess is that the keyboard and LED multiplex control is done in hardware and that the controller IC is latching up.
In order to reproduce the fault you need an early Pa2x, you need it hot and you need to work it hard in style play mode for a few hours, preferably also with vocal harmonies . Eventually it will lock up. Hopefully the labs will be able to recreate the lock up when they get their hands on my Pa2x next week.
I believe the Pa2x was released to the USA later than the release in Europe. It may be that the faults are confined to the early production runs, and that is why in the USA your customers have had fewer problems.
Thanks,
Rob