Fostex 812/820 MIDI Controller (8200) manual

[obiwanjacobi]

I have a Fostex 820 mixer with a MIDI Controller (8200) fitted. From the schematic I gather that it operates on the channel mute.

In order to test if its is working I am looking for the user manual that describes its intended functionality and what MIDI messages are received and sent. However my google-fu is lacking...

Does anyone know anything about this controller?

[Enzo]

Can your google-fu find a phone number for Fostex, and you can call and ask for an owner manual?

I see the circuitry in the schematic,but I have no idea what controlling devices are used and what information they must send.

[obiwanjacobi]

Yes, I have done that too
I wrote an email to the Dutch distributer (as I am Dutch) and he is now checking in Japan.

The MIDI controller / interface has one logical input and one logical output per channel. The channel cards are modified so that the mute button goes to the input of the controller and the output of the controller drives the mute signal. This puts the controller between the mute button and the mute logic circuit on each channel.
Note that the schematic is not very clear on how this is wired up and the channel card I have do not have the S103 on them. Instead, some wire links are cut that allow the controller to intercept these signals.

The problem I am seeing is that when pressing the channel mute button, nothing happens. I would expect that the controller would sense the input and send a MIDI (control?) message as well as toggling its output to drive the channel mute logic.

Apart from how it should work, I am fairly certain the MIDI controller is not working properly. Trouble shooting this digital circuit is probably unavoidable. Oh well....

[obiwanjacobi]

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