DX7II Sound Sources RAM cartridge

[SamSamba]

I have a Sound Sources Unlimited SX RAM 128 cartridge. I've tried googling but there is literally almost no data available for these, so I had to post here. Here's my problem.

When inserted into my DX7-IID (using the Yamaha ADP-1 adapter), pressing the [Cartridge] button gives me the "Cartridge Format Err!" message. When I then go into Edit mode, press [15] (Cartridge) and try to format (with the DX7's cartridge memory protection "off" obviously), I get "Memory Protected !".

The problem is - this particular cartridge doesn't have a physical on/off switch like the official Yamaha RAM4 cartridges, but a red push button (see photo below) with the labels "on" and "off" below it - and I THINK this is the memory protection function. Pressing it does nothing though.

The bank selector button does seem to work and the bank selection lights up. Am I dumb or doing something wrong, or is this cartridge broken?

[desmond]

I vaguely recall that when using DX7 mk1 carts in the DX7II, you could read from them, but not write to them...

[SamSamba]

I vaguely recall that when using DX7 mk1 carts in the DX7II, you could read from them, but not write to them...

I didn't know that. I found a message regarding this on the DX7 mailing list as well and it seems to be the case. Oh well

I guess most people with DX7-II's have the floppy version and then you don't have to bother with clunky RAM cards to begin with...