Hello there I’m new here I just came across a problem on my Podigy and looking for some help. I was playing the Prodigy with the SYNC OSC2 to OSC1 on and moving the INTERVAL when I lost the all sound to a high pitch sound. If I turn down the OSC 1 the sound goes away. All I’m getting from OSC1 is a high pitch sound, if I turn off the SYNC button OSC2 seems to be working fine. Can some please help
First, on behalf of everyone (mostly users like you) on this forum, welcome!
Second, have you tried moving the Sync switch back and forth a few times ? It could be dirty (or worn) and not making proper contact anymore.
And when the sync switch is off, does OSC 1 behave normally also ?
Let us know…
Oh, and also what is your Prodigy’s serial number (the electronics inside are a little different depending on serial number)
Al.
Thanks for the reply and the welcome! the serial #4400. I actually clean all the switches today with Deoxit before using it. It was working fine… I did try moving the switch a few times after, when the SYCN switch is off and turn down OSC2 on the mixer, I turn up OSC on the mixer and all I get is a high pitch sound. Thats all the sound I get from OSC1. If play around with waves forms and octaves switches on OSC1 the high pitch sound changes a little but if I move the INTERVAL the high pitch sound stays the same.
Okay. From what I’ve gathered so far: OSC 1 is the only one affected. OSC 2 behaves totally normally when SYNC switch is off. The timber of the high pitched sound coming from OSC 1 seems to change when different waveforms or octaves are selected for OSC 1.
BTW the “interval” knob only affects OSC 2, it is a “fine adjust” of OSC 2 frequency. So that is also working normally.
2 final questions: Does the pitch of the high pitched sound from OSC 1 seem to change at all when you play different notes on the keyboard ? Also does the pitch-bend wheel change the pitch of the high pitched sound ?
Answering these questions will help me pinpoint what could be wrong with OSC 1.
Yes the pitch changes when I play different notes and when I bend the pitch wheel
From all the info you gave, I suspect there could be something wrong with the exponential current converter circuit for OSC 1. The keyboard CV is still ok since it controls OSC 2 normally and also change the pitch of the high pitched sound of OSC 1. The oscillator circuit itself seems ok since it’s producing different timbre with the waveform switch and it IS oscillating and producing sound. Only the frequency control of that oscillator 1 seems to have a problem. Either the LF353 (U2 a and b dual op-amp) or less likely U1 the CA3046.
One thing you could try though, is to gently and very slightly nudge the “range” trimpot for OSC 1, accessible thru a hole identified in the back of the Prodigy. It could be a bad contact from the wiper of that trimpot. Be careful not to move it too much, and be sure to reposition it where it was as precisely as possible, as this will change the tuning of OSC 1 internally.
If that doesn’t fix the issue, you’d better have a qualified tech have a look at it.
Hope that helps.
Thanks for all your help! Out of the 5 moog vintage repair shops listed on moogmusic site, one happen to be in my home town. I took it in to have it looked at…
That’s great ! Let us know how it turns out… 