Sequencial Circuits Prophet5

I got a Sequential Circuits Prophet5 for a major overhaul.

It is a P5 rev3, the one with the CEM integrated circuits for Oscillators and Filters and it is in a very good cosmetic condition.

First it turned out that the owner had connected a new mains supply plug but unfortunately managed to connect the ground wire in the place of the mains, which resulted in having 240V on the chassis depending which way you put the mains plug in, ouch!

Ok, next when trying to power the unit, a tantalum capacitor blew up straight on the power supply! This is quite a common thing to happen on older equipment and tantalums are known to develop some bad habits when aging.

As the powersupply gets very hot during operation, all power regulators and capacitors on the board have been replaced, just to make sure that it will remain in good working order over the next couple of years.

Obviously it would be kind of a good idea to replace all tantalums in order to avoid any future blowups. I then exchanged all these caps to new electrolytic ones.

Voice board with Tantalum Capacitors still in place

Next on the list was a keyboard overhaul since all bushings had become hard over the years and the keyboard had that famous clunky feeling, all these synths using Pratt&Read keyboards develop over time.

For more info about Pratt&Read Keyboard repair follow this link.

And that was already it, all working as expected! Finally I replaced the old Lithium battery and restored the factory presets in memory. Now the synth is ready to go back to its owner.

Curiosities

It is well known that Dave Smith and his team of developers were a bit inspired by the Flower Power movement, an inspiration which we will eventually find back in the synthesizer, let’s take a look at some oddities!