Which way round does battery red and black go ?

[Multitasker101]

 

[Multitasker101]

I opened this old thing up to change battery and the wires snapped. I can solder them back on but which way round? Thanks in advance!

 

[kellys_eye]

Red to bottom corner.
Black to copper trace beside the tuning coil can,

 

[Minder]

If you measure continuity from one soldered point to the very rear of the power adaptor plug entry, this should be the positive, the other, will be the bl;ack.