Tape Deck Woes!

[LPTJoe]

I'm having some challenges with my tape deck, as per the title....

I have an odd and esoteric ICE isssue on my '96 940 at the moment where as whilst the radio on the car plays audibly and works well, when I plonk a cassette tape into the deck it appears to be playing it, ie not flipping it over again and again, all functions seem to work, changes sides properly when the button is pressed and generally seems to work, other than one small issue.... No sound seems to be produced!

Needless to say I've tried multiple tapes without success. I really wanted to keep the original cassette deck and I'm baffled that the radio plays and produces sound and yet casettes don't....

Any ideas before I bit the bullet and replace it with an aftermarket jobbie?

TIA chaps!