Switch to turn off external CPU?

[flinto81]

Hi. I'm trying to work out if its possible to disable the external cpu (therefore re-anable the internal cpu) without removing the adapter.

I was trying to work out the schematics and was thinking that an on/off switch on R1 instead of the Oohm jumper, would either enable or disable the bus takeover and therefore would work for this purpose.

Am I correct? If not is there another way of acheiving this? Many thanks