Recharging Nargra Pl-P

I traded a Nagra amp online not knowing too much about it other than the nice look and feel of its interface. Its seems that the row of D batteries are dead. I was wondering how to go about e-charging them. Or do I have to replace them? They appear to be soldered together and possibly heat-shrunk wrapped together.

This is the only reason I can think of why it would not power up, other than some other unforeseen damage, and likewise, a scam. But id like to think not.

Any suggestions?

Also, while i am at it, what sort of cables will I need to get this wired to a turntable and speakers? Any suggested brands or idea of price range? I these get to be too much I may try to sell this item, assuming it works,and at a significant discount. If that's the case, is the serial number shown inside, because there is nothing on the outside.

Thank you all.