If your are not seeing any MIDI messages coming out of the EX then I doubt it is the PC900.
I would suggest start checking voltages and waveforms (with a scope) around:
IC26, DTA1, IC27, DTC1, IC28. See the schematic.
Mike
From: ariebruus <ariebruus@...>
To: korgpolyex@yahoogroups.com
Sent: Thu, January 21, 2010 4:54:38 AM
Subject: [korgpolyex] Re: a broken ex800
--- In korgpolyex@yahoogro ups.com, Michael Hawkins <korgpolyex800@ ...> wrote:
>
> Also, change programs and see if the EX-800 is sending MIDI out program change messages. Then check the channel of those messages.
>
> Mike.
>
>
>
>
> ____________ _________ _________ __
> From: Electrohead <electrohead2000@ ...>
> To: "korgpolyex@yahoogro ups.com" <korgpolyex@yahoogro ups.com>
> Sent: Wed, January 20, 2010 9:55:47 AM
> Subject: Re: [korgpolyex] Re: a broken ex800
>
>
> I agree. Check ur channel settings. Try using a midi monitor program like midi-ox to make sure there isn't a problem with the computer you are using. Also try using a different cable.
> After that, then I'd start checking for a loose connection inside. Particularly if you've had it apart.
> Good luck!
>
Thanx, i'm sure i've got the right midi channel (midi-ox is sending on all channels). I've checked every possible way to make sure it isn't a cable or parameter. I've also checked with another midi device an that works fine. I use midi-ox to monitor the midi messages. The only time the ex sends out a message is when i turn it off and on again. Then midi-ox gives the message: device reseting. It doesn't send out a message when i change program or press start/stop (i guess it normally does send a message??). I did not check if there's a loose wire inside, will do that asap. I'll also try to replace pc900, but first fool around some more without using a soldering iron.