> Looking inside, I found one of the bus junctions (the one after the
> MIDI interface) had a small plug with what looks like a
> diode/transistor on a heatsink. Removing this stopped the interface
> recieving gate input.

Hi Stephen,
The little gizmo supplies 5V to the bus - without it, the A-190
won't work. Previous posts seem to have covered most possibilities,
but I can see one that isn't. To summarise:

You can stop the A-190 putting gate and CV on bus by removing links on
the A-190 board - I think you've checked this (its buried in the A-190
manual).
You can prevent the A-140 from receiving gate from the bus with a
jumper on its board - again, its buried in the manual entry for the A-140.
Bakis mentioned the same applies to the A-110 - couldn't find it after
a quick scan of the manual, but careful scrutiny of the board will
reveal this or not.
You need to have jumpers connecting the gate and CV signals on the
left and right halves of the system busboard - looks like you've
checked these too.

*In addition* if you have a G6 case, i.e. 2 rows of modules, you will
need a lead connecting the gate and CV bus signals between both top
and bottom busboards. I think the standard Doepfer one connects to the
jumper pins mentioned above - the one I have just connects 2 unused
connectors on each board. If you have a G6 case, and A-110/A-140
modules are on other row to A-190, this could be it( !).

Also, the A-141 *doesn't* take gate from the bus anyway, just in case
you have one of these!

If it's none of the above, then it looks like you'll have to get a
multimeter out and start measuring what voltages appear where!

Tim

[The views expressed above are entirely those of the writer and do not
represent the views, policy or understanding of any other person or
official body.]