Vintage Synth Explorer Forums

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..

Still not tuning...

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.

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...?

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.

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

I tried again but no success ..

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

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

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

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.

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

Good work.
Sharing my Mantra:

"Aint vintage FUN ???"

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..

+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.

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...?

Sent you a PM