Starter doesn’t want to start…

Moin in the round, today a problem from my side: Volvo 850 T5-R EZ 09/1995 The starter turns nciht more. On strike – just like that. Before still “normal” and inconspicuously driving around with the car, shutting down and – zack – nothing works anymore… Ignition comes, all lamps in the AI, KS pump promotes, dipped light etc starts, idle control valve hums. If then you turn the SChlüssel further… …nothing turns no starter, but also the light does not get darker. kt trigger (i.e. Abblendlciht goes off, switches are unlit), but otherwise completely quiet. So ignition start switch renewed. OE Volvo – part virgin. No change. Starter removed and “brimmed” on the workbench – works. All conveyor belts checked – are impeccable. New battery installed, also nix. Multimeter fetched and started to measure: battery has full power, even under load (is a brand new VARTA) the value does not change even during the tried start process. nlasser arrives full voltage (“dickes red cable” Only on the plugged cable I have not been able to determine reasonable values. What voltage should be there during the start attempt? When it comes to current and voltage I am really a beginner, so I hope to get one or two target-oriented tips on this way. Parallel to this I look at the circuit diagrams, maybe I can still draw useful information there… Markus