Permanent Live

[Crusher]

I have a 95 DTM with standard SC804 head unit and boot changer. The head unit has seen better days with a few buttons not working.

I have decided on a Vivaro radio which has similar pins and gives me an aux socket on the front.

Why can I not find the permanent live in the calibra pins in the multi plug? I have an ignition live but no permanent which pesters me having to put the code every time I turn it on.

What I can’t work out is how did the 804 retain memory with no perm live?

Thanks.