Hi all, just bought a pristine looking XS7 off craigslist. It played perfectly when I bought it. Brought it home and one week later the keyboard is acting up. Single notes work fine, but when I play chords or combinations of chords, it really glitches bad to the point where it’s unusable. I went through all of the diagnostic tests and everything passes. Took it all apart, vacuumed the keybed, check all connections, and the problem persists. Firmware is up-to-date and everything looks OK, just sounds like crud. Has anyone seen this or know what to do next?

A video of the glitch is here:

https://youtu.be/182fTNZYA_c

Thanks!

Dave

Welcome to the forum.

Besides an amp or headphones, if you have anything else connected (MIDI, USB, Ethernet, pedals), unplug those things and see if the problem persists.

Does it sound better on headphones plugged into the PHONES jack than on speakers?

If the “glitch” still occurs…
What mode is the XS in (Voice, Performance, etc.)?
Which Program are you playing (Preset or User)?

Can you attach a short MP3 example (not YouTube video)?

Thanks 5pinDIN. It sounds the same with headphones, amp/speakers. Nothing is connected but the pedal and I will unplug that and try it.

I’m in voice mode, using preset sounds, problem occurs on all the sounds I have tried.

I’ll capture an MP3 and post it.

Dave

OK guys, attached is an MP4 of the glitching sound. It’s not so much a glitch as it is a distortion when more than 2 keys are pressed simultaneously. Weird thing is that it’s not every key, just certain combinations.

OH, and no change with sustain pedal unplugged.

Dave

glitch.mp3  (File Size: 505KB - Downloads: 266)

What happens if you play the demo songs?

They play just fine. So, something with the keybed or the interface between the keybed and the motherboard? I poked around in there and it looks like a serial bus connection to the main board from the keybed PCB. What I found even more fascinating is that this thing is running Linux!

Dave

DaveKush - 02 February 2016 12:00 AM

They play just fine. So, something with the keybed or the interface between the keybed and the motherboard? I poked around in there and it looks like a serial bus connection to the main board from the keybed PCB.

Based on the demos playing OK, it does seem to be related to the keybed. Take a look at this…
http://www.motifator.com/index.php/forum/viewthread/476426/
...and see if you can get a full range of velocity numbers from each of the keys.

 

DaveKush -

What I found even more fascinating is that this thing is running Linux!

Dave

Yes, MontaVista Linux:
http://staging.mvista.com/download/fetchdoc.php?docid=28

Just did a bit more tinkering and found that it only glitches when 3 or more keys are pressed simultaneously. Two key presses together don’t make it glitch.

Dave

Did you reset the entire system?

Yep tried multiple factory resets to no avail.

OK, so I tried the velocity numbers on three especially “glitchy” keys. I do get a full range of numbers on these between 1 and 127 when pressed individually. However, when I press all three of them together even super slowly, it is always 127. But when I press three keys slowly that don’t glitch I get a more realistic (lower) number.

Dave

OK, I had a feeling that the “glitch” was related to excessive key velocity.

Is the problem more evident at one end of the keybed than the other (let’s say the top 2 octaves or so, versus lower down)?

Can you identify a group of keys where the problem repeats in different octaves?

Yeah, it appears that it happens in most octaves except the very lowest and highest with the group of F#,G#,A# pattern. However we have seen that group move by a key or two where sometimes you have to throw in the B to get it to glitch.

I just popped up a few keys and looked at the contacts. Even when I press on the rubber contacts with the above pattern, I can still repeat the glitch.

Dave

The G#, A#, and B keys (along with G, A, and C) in each octave share a processor line in the key matrix. However, the F# keys aren’t part of that grouping.

As a starting point, I’d suggest checking the interconnections between the MK76L, MKC, and MKH-D boards.

Do you live in a coastal region? High humidity/"salt air” has been known to cause corrosion issues.

OK. Can you point me in the right direction there? Are those PCB’s or interconnects? Are they on the key PCB, do I have to pull the whole keyboard out to get at those?

I’m not sure about the previous ownership. The guy I bought it from wasn’t coastal (Sacramento).

Thanks!
Dave

DaveKush - 02 February 2016 05:10 PM

OK. Can you point me in the right direction there? Are those PCB’s or interconnects? Are they on the key PCB, do I have to pull the whole keyboard out to get at those?

I’m not sure about the previous ownership. The guy I bought it from wasn’t coastal (Sacramento).

Thanks!
Dave

MK76L, MKC, and MKH-D are keyboard PCBs.

Do you have this?

Oh cool, that should help tremendously!

OH, and I confirmed with the previous owner that he did in fact purchase it from a guy in San Francisco area.

Dave