Yes as you correctly surmise this wire is to bring A12 to the Program Rom for the expanded Eprom as this track was not put on the main board originally. No this is not needed for the Upgrade and once removed it is probably best to either remove the ROM entirely or put the pin back in the socket so it is tied to something and not floating. The 3P Upgrade uses the existing RAM to store sequences but not programs. All the program and Patch storage is internal to the new CPU.

I do not believe Roland cut any tracks putting in this upgrade as the only change seems to be adding A12 to the ROM. So you should just remove the wire and then fit the socket as normal.

Regards
Murray

--- In kiwitechnics@yahoogroups.com , "rob_ocelot" <rob.ocelot@...> wrote:
>
> I have a KT upgrade on the way and I cracked open my newly reacquired JX-3P to get started on removing the 8031 and other things.
>
> Here's what I found, different from any other 3P thatI've owned:
>
> -a wire running from pin 26 of the Intel 8031 to pin 26 of the socketed EPROM
> -EPROM is an offical Roland ROM on a 27128 with '3' circled on the label.
>
> I'm pretty sure this is the often-mentioned Dynamics upgrade offered by Roland that allowed velocity over MIDI (routed to VCA and possibly VCF). I assume the wire is an extra address line that is needed for the expanded ROM.
>
> Now the big question to Murry is if this line is needed for the KT upgrade?
>
> I suspect that Murry's upgrade bypasses the ROM and the internal RAM entirely and has all of that contained on the 8031 replacement. However I think the Roland upgrade isolates 8031 Pin 26 from the main board so should that be reattached when I replace the 8031 with the socket?
>
> I think it's ironic that I spent years searching for this 'mythical' ROM upgrade only to find it when we finally have an upgrade that accomplishes that much coveted features and so much more.
>