bell + / - might be a good place to start ?

Okay, I will. Hopefully, it will work, I wired a siren into that terminal, and powered it on, and it went off, I couldn't stop it, no matter what, so it may be a constant 13v supply

just use a meter to test all outputs then you will know

Yes, I will do that, I know that there would be a very low voltage if I used the meter on a zone terminal, and 12v on an output terminal

maybe not on an old logic panel, probably 12v pos on the circuits. 0v tamper etc pressure mat days

Ah, yes, I really didn't think, there were probably no PIRs then, so you suggest that I just link out every terminal?

I'd test current passed first but yes bear in mind those days were not just nc and a lost was no

If you have played with unknown circuits, outside of security panels a meter will help loads

I made a pressure mat once when I was about 12, with foil paper and cardboard, no money no job , had to manually reset it of course , trigger when parents were coming buzzer would go off

I had a door

Okay, I am presuming a '24 HR'  LED on the front of the panel means a tamper fault?