Moog Music Forum

Hello, perhaps someone with greater knowledge than I can tell me what is wrong with my much-loved moog prodigy.

It works fine, except that the attack on the VCA stopped responding. It seems sort of "stuck" on a slow attack (around 2-3 seconds). Which is annoying in the extreme, since it takes out all the punchiness. Everything else works. I took it to one of the only shops in town that said they would work on it, and the guy says he thinks it needs a new IC chip for the attack circuit. Here's the second part of the problem. If he's right, and the IC for attack in the VCA is bad, where do I get that. He's tried the suppliers he uses and tells me the part is listed as obsolete. Well, obviously, it's old equipment. So does anyone know where to get a part like that for a prodigy?

Or does anyone have a suggestion, since the guy at the shop only thinks that is what the problem is. Could the problem be anything else?

Any thoughts or info that will help me get my punchy leads back?

Thanks!

What part is broken?
As I know all chips in a Prodigy are available.

The keyboard tech said it's the IC chip that controls attack, parts numbers U18 4007 and U19 4007 on the schematics. He said the chip controls waveform shapes or something, and that the places he gets parts from seem to list it as obsolete, and he can't find the chips.

But I don't know how much experience he has with moogs as he is mainly a Kawaii, Roland, Kurzweil tech. He's just one of the only guys around who said he could service the Prodigy. That's why I'm posting, to see if A.) someone who has a working knowledge of Moogs can tell me if the attack IC chip really needs to be replaced and B.) where those chips can be found.

I'm very sad without my Moog. I sit around, despondently plucking at my bass guitar...

Hey buddy.......

Life with out Moog is sad.... My Prodigy always has something going on.. Right now the Mod circuit only works between 10 and 30 hz. Other than that , it does not respond. I'm sure all the chips are available by some means. Kevin L might be able to tell you whats up, even though he will most likely not work on the synth (doesn't work on synths worth under $1000.00)... It could be a matter of a loose or chiped off solder point for the VCA attack Pot. Tons of possibilities. Also, a possibility that the VCA 10V+/10V- is off causing the circuit to malfunction in some way or another.I'm not a tech though, just making stabs in the dark. KL is probably laughing as he reads this..........

Speaking of prodigy repair I need a VCF sustain pot.. If any of yall know the hook up...

Nick

Your tech should try it here:
www.digikey.com
part number: 296-3501-5-ND

The IC 4007 is a standard CMOS-IC (CD 4007). You can order this part by any electronic distributors (it's not obsolete!).

The good thing is those chips in Prodigy are so cheap and simple ,that you shouldn't have any problem to find an exchange part .

BTW :

With two 20cm cable and one 2 pos switch ,your VCF envelope can control the pitch of the osc 2. !!!!! Incredible with Sync on !!!!!

I'll be happy to give you tips how to do this but i did it 3 years ago and forgot my schematics back home,Try to get them back.