TRS-80 Model 1 - How to Disable Ram in the expansion interface ?

@All

I have a Model 1 with 48K in the keyboard.

TRS-80 Model 1 - How to Disable Ram in the expansion interface ?

I can not find how to do it , I think that i have to cut a link in the expansion interface. (Somewhere)

I you have a link that would be appreciated

Thanks Ray