My prodigy osc 1 just started to give static noise and then no sound. Sometimes the osc will come back on for a few minutes. It happens on all wave forms and sync.
I’m going into the studio in two weeks and really need it. I’ll be taking it apart tonight.
Has any one had this problem? Any hints to what I should be looking for?
After doing some voltage readings last night, the IC U6 (u6a on schematic) had zero volts off pin 4. Is this a common component to fail? Or am I missing something before it that failed?
I don’t have a Prodigy schematic in front of me, but I know that IC’s fail quite often. Its probably a good place to start! Replace it and see!
Also, while this little guy’s apart, are there any mod’s that someone has done which are advisable?
Well, all componets will eventually fail, that is true with any electronic circuit. Resistor values change over time, capacitors build up moisture and fail, and IC’s just stop working! If you are good at soldering, it wouldn’t hurt, but it would be very time consuming and you might as well replace the resistors and caps while your at it! I say, if it ain’t broke, don’t fix it.
Replacing ICs as a guess is bad advice.
One can do more harm than the unit originally had and still have the first problem to deal with.
Mistakes can be made, traces lifted, wrong parts installed, etc.
IC’s do NOT fail as much as you might think.
Inexperienced “techs” always think of the IC first, but it’s the last thing I do.
The PCB is the largest single componet in a synth and has the most connections.
It sees the most flexing and opportunities for failure.
95% of all synths I restore have PCB problems while only about 2% need new ICs.
However, approx 20-30% of the synths I see are messed up because someone thought the ICs were the problem and made things worse.
Sorry for the attitude, but bad advice ruins synths.
If one doesn’t have the experience, skills and parts, they shouldn’t take guesses with their synths if they value them.
If they don’t value them though… have fun and use a big hammer! 
Kevin!
Slightly off-thread here:
Just stopped by the excellent Synthfool site and I note that you’re fully booked for servicing for this year. Well done! It’s always good to see that quality is appreciated and you’re busy. I also note that you have decided not to service smaller synths, but one thing puzzles me.
Whilst you aren’t prepared to service a Prodigy, a superb (albeit simple) synth which provides a cheap Minimoog subsitute for thousands of musicians, you are prepared to service an EDP Wasp, a nasty bit of cheap digital tat made out of recycled egg cartons which has been annoying musicians since the early '80s, when they were bought by schoolkids who couldn’t afford real synths and indeed knew no better.
Can I suggest that you stop this filthy practice at once? I have personally been trying to buy all the Wasps, Spiders, Gnats and (ugh!!) Caterpillars from eBay in the hopeful attempt to remove them from the World of Electronic Music. Each unit that I successfully purchase is ceremonially destroyed by subjecting it to high intensity ultrasound (derived from a Prodigy sinewave) and the resulting debris granulated, sent to the Highways Department and used to repair poor road surfaces here in the rustic Cotswolds. Oxfordshire has much to answer for being the birthplace of these nasties, and it is fitting that the repair of that fine county’s lanes owes so much to their demise.
I consider this to be a valuable Public Service.
Keep up the good work (not on the EDPs of course!) !
Cheers f’now!
HRx
I wonder if the EDP company building still exists. If anyone has the exact address I’ll go and take a look. I know its in Headington somewhere, about 20 minutes up the road from me.
Tell you what…
I have a wasp’s nest right outside the door here.
Yellowjackets.
Give me an address and I’ll make sure that your lust for these units is put to rest, once and for all.
Kevin:
Thanks for the post. I do not consider myself a tech at all. But, I honsetly don’t know of any around here (NH,USA) that will work on these either. I’ll be testing the PCB’s tonight.