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KN5000 new fault

Morning folks I have a KN5000 here with a strange fault that I am working on. I don't think it is possible to set this up as a function on the unit so am looking for a fix in the hardware. The fault occurs only in the right hand part of the keyboard an…

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KN5000 new fault

davetutt

davetutt
United Kingdom

Total Posts: 161
Joined: January 12, 2015

Morning folks

I have a KN5000 here with a strange fault that I am working on. I don't think it is possible to set this up as a function on the unit so am looking for a fix in the hardware. The fault occurs only in the right hand part of the keyboard and is most obvious when playing single notes when there is a definite drop in pitch by about a semitone when you hold a note for more than a second. 2 or more notes and it doesn't do it neither does it do it in the left hand section. It is not note specific, anywhere in the right hand section will do it. The sound becomes harder and sort of distorted too. Again though if you play a chord or a discordant noise it doesn't do it. My customer said it goes out of tune but actually it always starts on the right note and is, according to my frequency counter spot on as you would expect for a digital instrument. It gradually gets worse as it warms up. I intend to do some power supply renovations with heatsinking as appropriate but I am wondering if anyone else has had the problem and if anyone has found a solution.

I'll let you know how I get on!

Regards

Dave

Posted on March 10, 2015 at 8:18 AM
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2 Replies

admin

admin
United Kingdom

Total Posts: 1035
Joined: February 2, 2014

Re: KN5000 new fault

Hi Dave,

It doesn't sound like a power supply issue to me, not that I'm an engineer or anything lol.

Take a look at this post (could be your customer!)

http://technicskeyboards.com/technics-keyboards-forum/kn5000-right-...

Another candidate could be a footswitch socket with a short. This could be triggering the Glide function,which would detune one or more right hand parts by a semitone.

Another could be a sticky performance pad. If the performance pads are set to Control Preset then one of the pads (Pad 3 on KN7000) an be assigned to the Glide function. So a stuck-down pad could affect one or both right hand parts to detune by a semitone.

It would also be possible to program the keyboard's aftertouch to detune one or more parts. However, this should only affect edited sounds stored in the sound Memory group.

It is possible to program a sound to detune over a set period of time. Again, this should only happen to individual sounds stores in the sound Memory group.

It is possible for the vocal harmoniser to apply a detuning effect to one or more parts in certain circumstances.

I suppose there are other things that could make this happen, certain technichord settings or combinations of digital effects... need a bit more detail such as whether it affects all sounds, all notes, which parts, how long before it detunes, how much it detunes etc

When you think about all that it is a wonder that any of the instruments stay in tune for more than five minutes lol.

Good luck, let us know how you get on.
Mike

Posted on March 11, 2015 at 12:48 AM

davetutt

davetutt
United Kingdom

Total Posts: 161
Joined: January 12, 2015

Re: KN5000 new fault

Morning Mike

This fault is or was really weird! If you held a note down for between a second or 2 it would drop down by a semitone and stay there. If while you were doing this you played another key the pitch would return and all the keys would play normally. More than one key and it seemed fine although my customer tells me that it would go into drop mode even with full chords. There is no mechanism to cause this within the organ itself. The single note issue being most concerning as it suggests a registry issue and some dodgy processing writing things to key scanning ram. This machine has a split across the front panel between the two PCB's that make up the front control surfaces. There was some deposits on the boards from what looked like either a cleaning fluid or perhaps water. Of course the transpose buttons are here as is an IC associated with the scanning of the same buttons so I can'rt rule out this as being the cause. Once cleaned the fault seems to have disappeared although you never know with some of these faults.
The failed floppy drive however couldn't be so easily fixed. New disk drives and checking through the cabling made no difference. The power supply was fine so the reading of the disks seemed to be entirely due to the control chip. I did get it to read a few disks but it would never actually run what was on them. Unless of course I hit the wrong buttons! None of the bits downloaded from your web site actually worked so somehow I feel there is still a hardware level failure here. The original disks had been wiped so this would also suggest a control chip failure assuming the owner hadn't done it. But would you format both disks? And they were write protected too and the tabs were jammed so something else odd had happened here.
Talking of the power supply I had forgotten the layout of the 5000 and of course it is less likely to suffer PSU faults as it has proper heat sinking which means that life is likely to be rather longer. My thoughts on the issue were that i the PSU was at all noisy it might just upset certain aspects of the way the machine works. Given the odd character of the fault I guess I was clutching at straws!!!!!!


Thanks for the post Mike
Since the owner is an average user rather than a skilled user of the instrument I don't think any of the programmable functions would be in play in this case. Unless it came up on the screen in normal play or could be set by thumping the front panel during use I would think that the playing is very average. The fault is also apparently somewhat intermittent and although it occurred for me when I turned it on it could go some time without showing up.



Regards

Dave

Posted on March 11, 2015 at 8:53 AM