Nakamichi Cassette deck question DR-3

Hello kind folks!
I recently purchased a NAK DR-3 on ebay to record some high quality tapes for portable playing (on my Walkman).

The deck has an issue. When recording, the left channel is very low. The signal is low before I even hit record. YOu can see the levels are unbalanced. Yes, I can turn the dial on the balance but still...this bothers me. Yes, I have checked the cables. And I have used the same output from my amp on other decks with good results. Does anyone know what could be causing this and how to fix it?

Thank you for your time!
Brian Shunk
Fort Mill, SC
it requires service and may cost more to fix that the unit cost.
I should have posted a followup long ago! The dial just needed a quick spray of contact cleaner. The deck has been running beautiful and can hold it's own with my BX-300! Seriously.