1. General

To my knowledge there are two Midi retrofit kits for the Prophet 5. The original factory midi kit from Sequential Circuits, and the one from Kenton Electronics.

The original factory midi kit can still be ordered from Wine Country Productions. Kenton ran out of stock but announced it will be possible to order it again soon. Check at

Since I do not have information about the Kenton Midi kit, I only can introduce you to the 'factory Midi kit'. Maybe someone can spare me some details about the Kenton midi retrofit, I will be glad to put it on this page.

2. Sequential Circuits factory midi retrofit kit
2.1. Manual and specifications
To know the capabilities of this midi retrofit, you can read the last page of the installation manual.
Factory MIDI kit installation manual.pdf
To know what messages can be transmitted or received read the Midi implementation
Midi implementation.pdf
There are also some important notes that you should read when you want to perform midi dumps.
How to perform a midi dump.pdf
Example of an System Exclusive message explained.pdf
Program number conversion table.pdf
2.2 Installation

This retrofit is only possible on Rev 3.2 or 3.3 models. The pictures below show a retrofit on a Rev 3.3 model. Installing a Midi retrofit is not easy and should be done by an experienced synth technician. Installing involves soldering and cutting of traces. For soldering the wires you need an experienced and steady hand.

Factory MIDI kit installation manual.pdf
Picture Midi 1 : Midi in and out jacks - installed on location according the installation manual
Picture Midi 2 : The wheelbox before the installation, room to spare

Picture Midi 3 : PCB 3 before the installation, below the EPROM (recognisable with the sticker 9.5) is room provided for

an extra EPROM Socket
During the installation 6 wires, and 1 EPROM IC socket, have to be soldered to the PCB 3 circuit board. On the picture below you see the 6 white Midi wires. The other green wires are original, and were already present.
Picture Midi 4 : The white soldered wires of the midi kit
Also 3 traces have to be cut. One of the 3 traces is located on the front of PCB 3 shown in picture 5.
Picture Midi 5 : Cut trace on the front of PCB 3
Picture Midi 6 : Midified PCB 3 front
Picture Midi 7 : Midi Jacks mounted in the bottom panel
Picture Midi 8 : The midi PCB installed

The Midi PCB contains two commucations IC's when it is completed. One is the original moved 2651N USART, the other one is the SCN2661AC1N28. Both IC's have the same function. The 2661 is a newer type. One is for the midi communication. The other one is for the communication over the Prophet 5's Digital interface.

Datasheet SCN2661.pdf

Picture Midi 7 : The Midi PCB with connector