Do mean MRC Control Master 20 ?
I have 2 of them, But I dropped one and broken some wires inside.
MRC uses tamperproof screws I cannot find anywhere, or a tool to remove them.
If MRC no longer supports this product, then the screws will have to be drilled or ground off to open the case for repair.
Would you like to rid yourself of them? cbqer@aol.com.
Dick