New knob caps for Prophet-5/10/600, Pro-One etc

Painted vs new
Ugly old painted Prophet-5 cap (left). My brand new cap (right)

I bought a Prophet-5 where the black caps were painted black… it looked absolutely awful. Searching the web for replacement knobs (like I’m sure many of you Prophet owners have) only turned up extremely expensive old stuff, which usually was “out of stock” anyway. I did get hold of some original replacement knobs, but these were pretty scratchy and worn too.

I decided to fix this! I had a company re-manufacture the aluminum cap to the exact original dimensions. (I also looked into making the plastic knob part, but then I realized most people already have these and they usually look ok).

The old caps are easy to replace, they basically pop off with the help of a knife blade. There is a little dot of glue in there that doesn’t provide much resistance 🙂

Now, only the more high end SCI gear (Prophet-5, Prophet-10 etc) had the fancy knobs with aluminum caps. The more low end stuff (Pro-One, Prophet-600, Split-Eight etc) only had the plastic part of the knob, with a simple painted white indicator line. The best part is that now you can pimp these models too! Many vintage (80s) Sequential Circuits gear used the same plastic knobs, with this cap being the only difference. The T8 and some other machines used different wider and shorter knobs, and unfortunately my caps will not fit those.

The pic below shows two old Prophet-5 knobs, one with a silver cap, the other with a removed black cap. Next to those a Pro-One knob. And in the bottom right corner: old knobs given a second life with my new caps!


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A Pro-One, Prophet-600 and Prophet-5 all recapped:


Sequential Circuits Prophet-5 – panel replacement

I have a Prophet-5 that is in pretty nice condition except for a nasty dent in the black front panel.


I have been thinking about if it’s possible to fix it, and asking around on how to approach it. I got a lot of good tips in my fav Facebook group Vintage Synth Repair and Mods

The consensus there seemed to be that it is sometimes tricky to fix these kind of issues. It is possible that ‘fixing’ the problem may result in things looking worse.

The paint has been stretched, and will likely crackle if pounded flat. Using a heat gun to warm the panel (and the paint) could possibly help to avoid that.

There are also quite a few companies that repaint old synth panels, but none of them seem to be capable of doing the typical ‘grainy’ texture that many vintage synths have.

The best way to fix it would of course be to replace the panel with a new one. I asked around but was not able to locate one.

But then one day I was talking to a friend who works for a Swedish super-producer with many many many synths in his collection. He mentioned that they had a “organ donor” Prophet-5 in their warehouse, and that he would take a look at it next time he was there.

And yesterday he called with good news – the panel on it looked fine and I was welcome to have it!


And there we are. (Jan 22, 2016).

UPCOMING: Panel switcharoo!


Oberheim OB-1 – Knobs smashed (and fixed)!

I have a near mint Oberheim OB-1.Super nice synth!

OB1 and TTSH

While it was waiting to get moved down into the “synth cave”, I had it standing on its side in a hallway. It felt safe, it was clearly visible and there was a smallish pillar/corner that offered some protection. Or so I thought.

One day a co-worker walked by a bit too close and it went BAAAAAMMM – falling and landing upside down on its front panel. F**K!

But this synth is built like a tank – the only things that broke were the small plastic ‘caps’ on top of 4 or 5 of the knobs.

broken_knobs  taken_apart

Now. With a semi-rare synth from 1978 I do not expect finding replacements would be easy. I checked the usual channels (ebay, syntaur etc) but came up empty handed.

I also looked into alternatives like plastic caps for furniture.

But then my fav Facebook group Vintage Synths Repair and Mods came to the rescue:


And yep. Farnell had these exact knob caps in stock – almost 40 years later. Style never goes out of style?

I ordered a ‘full set’: 20 black and 10 gray. In case they looked slightly different from the originals, I wanted to replace them all. But it turned out they looked identical!


All well that ends well.

Next up for this Obie is probably to replace the PSU as it currently is 110V. Maybe a little cap refresh. And MAYBE add MIDI.. Not sure if I want to since this is a very mint machine.

Sequential Circuits Pro-One – broken front panel spacer fix

STATUS: Done! (Nov 13, 2015)

The Pro-One has spacers welded to the metal front panel, onto which the main PCB is attached with screws.

On my Pro-One, one spacer had broken off. (It was still attached to the PCB though).

Spacer overview

I decided to glue it back using epoxy glue. I sanded both the spacer and the surrounding panel a bit.
sanded spacer

Now, to get a good result I needed to add some weight/pressure to the spacer once the glue was in place – but also make sure the spacer was glued at a perfectly straight angle.

I came up with a pretty clever solution if I may say so myself: I fastened the spacer to an old transformer (the one I replaced in the Pro-One).
so clever
This gave me the needed weight AND a straight angle.

curing epoxy
A little epoxy on both parts did the trick. The other end of the transformer rested on a piece of wood of the same thickness as the spacer.