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Schematic for Verbos Touchplate Keyboard needed
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Schematic for Verbos Touchplate Keyboard needed
Randy
Some time ago I bought a used Verbos Touchplate keyboard from someone on the forum (can't remember who). Although it behaved oddly from the day I got it, figuring out it was the keyboard and not my rack took me awhile.

At first Verbos tried to help, and I even sent it back to them for repair. They repaired a small defect I had caused and told me it was fine. It was not fine, the existing intermittent problem with the groundplane (the local shop found it very quickly) was neither found nor fixed and now one of the gates has stopped working.

Verbos has decided to ignore my query this time around, and a local shop cannot do much without schematics.

So, one of two things is going to happen. I am either going to somehow find schematics and figure out a way to fix this, or I am going to take a video of me destroying it on my table saw and post it to Youtube. Either of those should be interesting.

Asking here for advice is the final stage, cue dramatic music.

Thanks

Randy
Grumble
Will it blend? hyper
Randy
Grumble wrote:
Will it blend? hyper


I'm fairly sure my table saw will handle it but I think the blender would be a bit worse for wear afterwards.

I'll keep that open as an option 'though.

Randy
Synesthesia
it's tricky to find schematics of commercial products.... I would think only Mark could give it to you...

I would insist and try with Mark again.
Jarno
High resolution scans of both front and back of the PCB's? This will at least help in determining the working principle. There are only so many ways to create a capacitive sensing keyboard.
Randy
Jarno wrote:
High resolution scans of both front and back of the PCB's? This will at least help in determining the working principle. There are only so many ways to create a capacitive sensing keyboard.


I'll do that before they hit the table saw.

Randy
pre55ure
The Schematics for the 218 are findable on the net. Not sure how close the verbos follows those schematics, but it could be a good starting point.

Which gate output is it?
Jarno
Hrrmmm, just had a look at the pictures on Schneidersladen. White pcb, hard to make out traces, maybe the names on the ic's tell us something.
Regardless, as mentioned above, persist to get Verbos to offer service or schematics.
Randy
The traces are very difficult to, uh, trace. It's the main keyboard gate out that's toast, the other works.

I'm not usually in the habit of chasing manufacturers to help me out with a screwy product but I might give Mark a try. The only method I can find is Facebook so perhaps I'll start there.

I bought it used so none of this may be Verbos' fault at all. But when I paid to return it and they decided it was fine, and it certainly was not, I ended up a bit ticked off.

Randy
Jarno
And all of the other outputs work? If the CV out is still ok, it might be an isolated piece of circuitry which is perhaps not too hard to figure out (either comparator and an output stage, or just an output stage).
Randy
Jarno wrote:
And all of the other outputs work? If the CV out is still ok, it might be an isolated piece of circuitry which is perhaps not too hard to figure out (either comparator and an output stage, or just an output stage).


No, it's never worked properly. The CV outs from both keyboards would sometimes work fine but most of the time they would start spitting out random bits of notes. If I touched one of the jacks with a finger while playing, it would work fine, which caused me to think there was a ground problem.

When I couldn't isolate the problem, I exchanged notes with Verbos, and eventually sent it back for repair. They could not find a problem and sent it back, proclaiming it fixed, which it was not.

I have tried on several racks and various power supplies. The local repair shop also tried but could not fix the issue. They did however notice the problem with the ground immediately, which Verbos did not.

This is the second time I have bought something from someone on Muff's and it has turned out to be defective. Both times were expensive bits unfortunately, and since it is difficult to prove the problem existed before shipping, both times I was out-of-luck.

On the upside, I'll get some nice red Rogan knobs as spares after I cut the keyboard into little bits.

Randy
flts
Randy wrote:
No, it's never worked properly. The CV outs from both keyboards would sometimes work fine but most of the time they would start spitting out random bits of notes. If I touched one of the jacks with a finger while playing, it would work fine, which caused me to think there was a ground problem.


This may be obvious but...

You say you tested the unit with multiple supplies and ditto the local shop, but were any / some of them wired with proper path to mains earth? Many touch keyboard designs (I'm not sure about Verbos) require a proper path to mains earth not to be completely messed up, so if all the supplies you tested with were floating, and the one Verbos tested with wasn't, that might explain the difference.

At least I've had similar experiences with certain other touch surface / kb modules that they are finicky about what kind of power supply is used with them. Eg. Make Noise René and Pressure Points start acting in a pretty erratic way without a properly specified PSU.
Randy
I am assuming the repair shop has a proper setup, they do some amazing work on vintage and modern equipment. While I was there I saw a Rhodes Chroma, Oberheim 4-voice, Juno 60, Minimoog, etc.

In my case, I recently installed ground busses for all of my power supplies, which had no effect.

Either way, a power supply issue would not explain why one of the gates recently stopped working.

Randy
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