HP12C battery contact question

[MikeE]

My first post here & hoping someone can help me before I damage my 12C !
My 3-cell 12C often failed to turn on unless I re-seated the cells. Now that no longer works and I have looked inside for the reason. I see that the -ve terminal seems to be a tab on the PCB which makes NO electrical connection to the battery. But there is a small copper strip almost at the edge of the PCB tab which MAY have had a wire or spring pressing against the battery's -ve terminal.
Can anyone confirm that this IS the 12C's -ve connection to the battery pack; the +ve terminal is well-connected to the +ve terminal of the battery pack via compression spring ? I am hoping that a secure repair/restoration between this copper pad and the battery will reinstate perfect operation.
Many thanks,
MikeE