Replace Impedance Selector JCM 800 Valve Amp

[Wriggle]

Hi
I wonder if someone could help me with the wiring of a replacement Impedance selector.
I can handle a soldering iron and have carried out some fairly complex mods on my valve amps using graphic directions though I am NOT an electronic engineer and cannot even read a schematic diagram.
I have attached a photo of the old selector (still wired) and the brand new replacement.

The new one has terminals 1-6 plus the earth in the centre.
Could someone please just tell me which colour cable (green, purple, yellow & black) goes to which of the 1-6 terminals and if I need to add a jumper cable from earth to one of the numbered lugs (with the black cable)

The old selector does not have any numbers on the terminals...

Thanks

Marshall Ohm Selector 1 copy.jpg (240.13 KiB) Viewed 1093 times

[SDM]

100 watt wiring would be:

Black wire (the one headed to speaker terminals) = "P" (center terminal)
Other black and the purple wire (should already be together on the original switch) go to 4 ohm/terminal 1
Yellow to 8 ohm/terminal 2
Green to 16 ohm/terminal 3

That's it, done. No jumpers, no earthing here.

[danosol]

There is also a black wire going from the board to the original impedance selector. Where does it go on the new selector?

[danosol]

The one in question goes from the DI to the selector which is jumpered to the 8 ohm by a resistor.