Korg Forums

Hal2001 · Senior Member Joined: 26 Feb 2011 Posts: 367 Location: US

Hi all. My first plea for advice in 3 years. While I play my 1st gen K88, all the notes suddenly take a nose dive, detune themselves, and go very flat. The effect is exactly the same as if you were playing guitar, and I turned all the tuning knobs loose while you were playing. I did not make any system changes during this time. It happens with both combis and programs. Examples of combis (but not limited to this) are pianos, guitars, pads, strings, orchestra, organ). Examples of programs (not limited to) Guitar, EPs, Motion Syr. Happens with or without any Karma. Detuning effect can happen at the end of an all day perfect session or can happen right after boot up. It's not Set List related as I've opened combis and programs in unused new Set List slots and it's still a problem. Program Piano sounds seem somewhat less affected, however the Piano programs can appear flat to begin with. Combi Piano sounds are very susceptible to the nose-dive effect. All functions on the keyboard work as if nothing else is wrong. Global Master Tune is set to normal 440 HZ. Has anyone experienced this? Any thoughts appreciated before I try a full reset and if that doesn't work, I'll try a restore with the disks. Thanks. Hal
_________________
My Music: www.youtube.com/Halunlimited
Kronos 88 and Genos, Logic Pro, Omnisphere

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 7860

Sounds like your pitchbend potmeter is dying. Happened to me too recently after a little over three years of ownership. It's a simple (if finicky replacement).

Hal2001 · Senior Member Joined: 26 Feb 2011 Posts: 367 Location: US

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 7860

I guess you could order a complete kit, basically you only need to replace the pot(s). The finicky part is that the actual module consists of a bunch of small parts that click and screw together, there's two springs too.

I did it myself but at the service center. I got the parts from them so I didn't actually look which pots they were. If you have time and you're handy enough you could takr them out and see (or measure).

By the way, as a quick test - what happens when you jiggle the pitchbend lever after a "nose dive"? Does it jump back and then center normally?

Hal2001 · Senior Member Joined: 26 Feb 2011 Posts: 367 Location: US

Rigel · Posted: Wed Aug 12, 2015 9:28 pm Post subject:

My Roland boards need (and provide as a menu option) pitchbend/modulation calibration. I suspect Kronos needs a calibration, too, though I know we dont have such a menu item in the usual user interface, but it may be hidden somewhere in the service menu.
_________________
Korg KronosX73, Kurzweil PC3K6, Roland V-Synth GT, Kawai K5000S, Waldorf Blofeld, Novation Ultranova, Behringer Neutron, Yamaha HS80M, Boss Micro BR80, Zoom H6, Sony PCM D100, Tascam DP32SD, Mackie 1202VLZ4, Zoom MS-70CDR, Rode NT1, Sony MDR 7506.

geoelectro · Posted: Wed Aug 12, 2015 10:22 pm Post subject:

If you're not using pitch bend to can disable it per patch so it won't retune your sounds until you get it repaired.

Geo
_________________
Kronos 61 : 3GB RAM 120GB 2nd Drv.
Kronos 2 61
Synthesizers.com Custom Modular
N.I. Komplete 11, Omnisphere 2, VB-3.
HP i7 8GB Win 10
Yamaha P-80 Weighted Keyboard. NanoPad2

ronnfigg · Posted: Thu Aug 13, 2015 1:13 am Post subject:

I had the same problem and fixed it myself. You can get the whole subassembly really cheap and it is easy to install. A few screws, a few connectors and a couple of zip ties. I think the company that has them is called Parts is Parts, or something like that.
Just found it. Here you go:

http://www.guitar-parts.com/
_________________
"To me the synthesizer was always a source of new sounds that musicians could use to expand the range of possibilities for making music."
Bob Moog

ronnfigg · Posted: Thu Aug 13, 2015 1:15 am Post subject:

Hal2001 · Senior Member Joined: 26 Feb 2011 Posts: 367 Location: US

Thanks SX, Rigel, Geoelectro, and Ronnfigg. You're all awesome. Thanks for pointing me to the likely trouble area.
1. Did you replace just the Joystick or also the IC associated with it?
2. I would like to disable the pitch bend but can't find the correct menu and tab. Can anyone direct me to it? (In Programs I went to P4:Basic/Vector Menu choosing "Controllers" tab. There are 8 different "JS" related options listed under SW1 and SW2. I tried turning to "Off at that dropdown tab (where the Safety Pin is) but nothing happens. Maybe that's for the Vector joystick and not the pitch bend. Similarly with the Combi menus.
3. Will I have to separately disable the JS in the Combis I use or will they automatically be disabled when the programs inside the combis have been individually disabled.
Thanks again for any suggestions.
_________________
My Music: www.youtube.com/Halunlimited
Kronos 88 and Genos, Logic Pro, Omnisphere

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 7860

The annoying bit about nine engines is that they each have their own places to adjust stuff Wink

Usually it will be on a "pitch/common" tab or somewhere near pitch parameters, rather than controllers.

Hal2001 · Senior Member Joined: 26 Feb 2011 Posts: 367 Location: US

I am going to order the Joystick module (It's only $30 from Parts Is Parts - Thanks for the link Ron). I've never opened the K before. Can I assume that when I remove the bottom wood board screws (except for the feet) the rest of the keyboard and chassis is totally intact? I.e. I'm assuming that if I'm very gentle in every way with turning it upside down onto a gym mat, and then remove the wood board, the keybed should not shift by itself. To be safe, I'll even tape the original cardboard spacers into the inside of the channel strip. Did I assume correctly? Thanks. Hal
_________________
My Music: www.youtube.com/Halunlimited
Kronos 88 and Genos, Logic Pro, Omnisphere

ronnfigg · Posted: Thu Aug 13, 2015 10:56 pm Post subject:

You're disassembly procedure sounds about right. I have never done that on an 88, at least not for the joystick. Putting the spacers in is a good idea. As far as the pitch bender subassembly goes, it is fully self-contained. All you will have to do is remove the connectors with the wires and snip a few zip ties and then put everything back on to the new pitch bend assembly. You will probably find it quite easy once you see what I'm talking about. I wish you success with the project.
_________________
"To me the synthesizer was always a source of new sounds that musicians could use to expand the range of possibilities for making music."
Bob Moog

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 7860

The keybed is held by the bottom plate so you will have to fuss a little to put it back exactly right. If you have the spacers that will help. Other than that, just be careful, make pictures and remember where the screws go.

vstkeys · Full Member Joined: 20 Mar 2011 Posts: 158

Wow I had the exact same detuning issue at rehearsals last night !!!!and just picked in here wondering if anyone had the same issue .
So today I've got my keyboard set up and the only way to stop it from the flicking through "barbaric tuning" was pushing the stupid slide thingy that I have never , never used before. First time it was used was the last night! My friend started messing around with the brass sounds trying to do a Cresscendo same way he does at his triniti and bang everything went out of tune.

So in my case if it is a problematic slide what do I do ?? do I replace it the part or there a way of readjusting or just cleaning it?