TB resuscitation

As mentioned in latest purchases I’m restoring one of my 303s, it was bought in 2005 as a wreck that came from a hire companies service department, it had no CPU, missing pots, and a few ICs had been harvested from it. It was in a sorry state.

I fixed it up and added a acidlab mod kit, unfortunately the kit wasn’t built onto a pcb so there were lots of flying wires inside and it was a bit flakey, then it stopped working so I put it away with the intention of fixing it one day. Years passed, it needed a new case as the old one was a bit knackered, so recently I decided to get a alu RE-303 case and fix her up.

This 303 always sounded the best of any that I owned, the resonance and filter interactions were somehow always sounding more “emotional” :laughing:

Anyway so a few days back the case arrived from Kumptronics and I set to work, I decided to remove all the acidlab mods and do a proper restoration.

Once I removed all the mods it was then a case of figuring out why there was no sound, a cut trace was the culprit, so I fixed that and now there was no resonance, I fitted a resistor and bingo she sprang to life!

Progress so far:


I don’t care what anyone says, there’s nothing quite like the sound of a proper 303. Absolute magic.
Massive credit for bringing another one back into the world.


Cheers @Fin25 still got quite a bit to do, but happy with progress so far :+1:


Beautiful. Truly beautiful machines. I realize that most of what I do with synths is trying to re-create that raw sound and (truly) emotion.

If I may lazily ask, what is the current best source for new buttons. My pots have always been fine but I have several with double triggering buttons.

You should mod one of those “I didn’t rescue my dog, my dog rescued me” posters/t-shirts/memes and replace dog with 303


AFAIK Circuitbenders.co.uk have buttons, think that you can get them from Dinsync.info too.

I rescue dogs and 303s, both bring me so much joy :heart_eyes:


Nice job :+1:t2:
I’m all about bringing gear back to life.

It saddens me to think how many pieces of repairable gear are in the landfills.


I found some old photos of what it looked like when I got it, note the components soldered to the back of the PCB, those were most likely done by Roland indicating that this was a very early one, the other two that I nave do not have them.

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Great to see someone who saves old machines. It is so exciting to see when skills and effort give another lease of life to a “junk”. Thanks for sharing.

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Bit more progress today - new clothes, midi finished. :laughing:

Still quite a bit of work to do but all working, pretty stoked, I thought I was gonna have more issues than I did, blue leds are going to be replaced with stock red, some wiring tidy up to do, a few mods but no sound ones as I love the way it sounds stock, just vcf cv and a couple of others.


Hurrah! Nasty blue LEDs swapped out for decent 630nm red, much nicer but a pig of a job in this heat and when my desoldering station decided to need a total unblocking, still all done and working now, 3hrs to do what would normally take 30 minutes.

Good choice. Blue leds can be nice here and there but on a dark stage or dim studio the mostly just blind you.

In the case:


Added VCF CV input and battery power, the case does not allow for the original 4xD cells, so I used a 4xAA holder with a battery snap connector, it just about fits. I decided against adding other mods, CV for VCF is really all I need. It also has midi in and out.

So it was a nice little project, I’m glad that I decided to do it, the dinsync RE-303 case isn’t quite a perfect fit for a TB-303 but is great quality and a huge improvement over the original case. I will probably get my own cases made for this and my other 2 303s.

Pic of VCF CV in: