Mopho Keyboard Pitch Wheel

[thedood]

Hi.
I recently bought a brand new Mopho Keyboard. It had been purchased years ago as a present and never used.
The problem is with the pitch wheel.
As soon as you touch the pitch wheel after turning it on, it detunes around a semi tone.
If I go to the patch and set P.W to 0, then move the pitch wheel, it goes back into tune.
If I set P.W to any value then hit the pitch wheel again it goes out of tune again.
Obviously either the pot is faulty (although it works fine otherwise, as in its very linear when turning it) or I need to calibrate the Mopho.
The only problem is I cant find a calibration routine. There is one for the SE and the x4 but it doesn't seem to work on the Mopho keyboard.
Any suggestions would be welcomed.
Cheers
Brett (Thedood) 

[will.taylor]

I've never had this happen to me before, but the manual suggests resetting global parameters and running the calibration routine if you run into any problems with the Oscs or keyboard behaving weirdly.

You can reset global params through the Global menu (hold Program button). Calibrating the oscs and filter can be done by holding Compare and Osc shape buttons.

I think the calibration routine only calibrates the oscs and filter, but it wouldn't hurt to try in this case.

[thedood]

Thanks so much for the advice Will. i never thought of trying that.
Ill give it a shot tonight when I get home and see how it goes.
The only other option I can think of is to insert a small say 2k pot in between the 10k pot which is the pitchwheel and tuning it till it sits directly in the right spot.
Currently, if any patch has a PW setting other than zero, as soon as I move the pitch wheel it instantly detunes a little. Obviously because the centre of the pot isn't calibrated perfectly to where the mopho analog convertor expects. I was hopeful when I seen a calibration routine but found it strange that it only existed for the two other models. (SE/x4)
Cheers

[thedood]

Well the Osc calibration did nothing unfortunately.
I removed the pot, and measured it as it sat in the centre position, this thing is brand new so the spring assembly etc was stiff and centred perfectly. The problem however was the pot. When sitting in the assembly it measured 6k one side of the wiper and 4 k roughly on the other, which explains my problem.
When centred the pot was way! off being a 1:1 ration of the total resistance (10k)
This had to have been faulty from the factory, Id say the reason I got it so cheap was because it never got returned for warranty. It still has all the plastic adhesive scratch resisting on all the keys and the screen, its like brand new.
Even a calibration routine possibly wouldn't have worked as it was so far out of whack.

So all I did was ground off the metal inset on the pot that keeps it in position on PitchWheel assembly, and tightened it off so the pot was sitting 5.2k/5.2k with some loctite .... dead centre 1:1
Works perfect now. Pitchwheel gets 12+- either side and it never drifts after turning it on - it's surprisingly linear considering the pots obviously not linear and closer to a log lol.

Cheers
Brett

[will.taylor]

My next thought would have been the spring mechanism, too. I'm glad to hear you fixed it yourself, rather than selling it on or junking the synth. These are great machines! Kudos for updating your thread with the fix too.

I saw a brand new MoKey for sale on eBay AU a couple weeks ago which seemed like a sweet deal. Was that the one you purchased?

[thedood]

I saw a brand new MoKey for sale on eBay AU a couple weeks ago which seemed like a sweet deal. Was that the one you purchased?

Lol...thats the one! After checking the sellers name, Ive realised they owned Hutchings Keyboards in Sydney years ago. So yeah, Im guessing a customer brought it back, and it never made its way back to DSI for whatever reason.

[Laszlo]

Any answer for the question:
How to calibrate the wheels?

The wheels, not the osc!

[Robot Heart]

What OS do you have on your Mopho Keyboard? The wheel calibration was added in version 1.2.6, so it should work if you're on the latest main OS. If you need to update, be sure to update both main and voice (power cycle in between updates).