Has anyone tuned a pro-one..?

[sam]

Just fixed a pro-one....It had many problems and all the trimmers were messed with ect.

I have done the tuning procedure from the manual...But it's still not getting there.

The cv scaling is fine.

Any tips or insight or moral support needed..

[sam]

Still not tuning...

[Solderman]

Only thing I can suggest is make sure the pitch wheel is centered, and you are getting continuity from the master tune pot. Might want to check the +15 and -15 volt supply sources too.

[sam]

Thank you solderman.....Everything checks out that you mentioned.

On the set up guide...You tune osc A with osc B NOT tracking the keyboard...?

[Solderman]

The tuning procedure does mention it, but I'd guess it shouldn't matter since the keyboard voltage is buffered. I think they recommend that so you can have a fixed tone for tuning Osc A, without an external tuner. If you've done everything in the procedure and the mains voltages check good, then it will likely need repair.

[sam]

I feel it's me and not the synth...I will try again....

[sam]

I tried again but no success ..

Should I....Change the power supply caps and the trimmer pots..?

Something is unstable...Any thoughts....????

[Solderman]

Doubtful it's either of those causing tuning instability. Best get it checked out by a tech.

[sam]

The so called techs around here are very bad....I enjoy fixing my own synths and never have needed a synth tech.

Anyway I have noticed some bleed through on osc B.

I have changed the caps and it's not too out of calibration now....I just need to make it perfect.

[sam]

I cleaned the switches again and found a bad solder joint on the osc B section...It is now tuning ok.

[rhino]

Good work.
Sharing my Mantra:

"Aint vintage FUN ???"

[sam]

Cheers Rhino....I spent some time on fixing it's initial problems and then tuning is just a finishing touch (I thought)

Anyway it's sorted and sounds good.

I had to fix the crappy membrane keyboard. I found a way of doing this by wrapping tape around the part of the key that touches the bubble...It seems to work...So far..

After this fix I can give some tips on how to work on a pro-one..

[Solderman]

+1 well done on finding the problem. I've got one of my own with my CS-15 currently. Noisy VCA's, even after changing all the electrolytics. Guess it never ends.

[sam]

Cheers Solderman.....What do you mean by noise...?

Can you hear it from the osc...What i mean is have you detected where it starts...?

[Solderman]

Sent you a PM