Kel84 input oddity

[Calorgas]

Hi All, I bought a 2nd hand Kel84 (upgraded to xl) a few months ago. It sounds really good and sounds every bit as nice as I'd hoped for. It works perfectly apart from one thing; the Tuner and Aux inputs are somehow joined. So with the tuner connected to the Tuner inputs I get the tuner playing whether I have Tuner or Aux selected. If I remember rightly the same issue applies if I connect a source to the Aux input - same output whether Aux or Tuner selected. So this prevents me from having things connected to the both of those inputs.

I did peer inside just after I got it to see if I could spot anything obvious but I couldn't see anything weird - though I must stress that I have no technical ability, just thought I might see touching wires on the input selector tags or whatever.

Anyone have any ideas, or recommendations for someone to help me fix it (Yeovil area)?

Dave