Blaupunkt is PP or SE?
If PP - 3 wires are primary....if max resistance is for ex. 400 ohm and 1 wire gives 200 ohm - 2 wires 400 ohm are plate wires and 1 is middle with 2 x 200 ohm for +B.
Remains wires are for speakers 4 and 8 ohm with res about 1 ohm. You must find middle for 4 ohm. 1 is ground, and next are for 4 /res. about 0.5-0.7 ohm/ and third is for 8 ohm with res. about 1 ohm.
If Blaupunkt is SE, 2 wires will give You more 200 ohm.