Corrosion damage from a leaking battery (btw, it's a base, not an acid, NiCd uses potassium hydroxide electrolyte) can be very sneaky.
Even if a trace *looks* intact, test it anyways. Test EVERYTHING within the affected area for continuity. Don't overlook via and through-hole plating, the stuff loves to eat those away and create open circuits.
Very likely something in there is still open-circuit.
When repairing corrosion damaged traces, go all the way back to a completely unaffected part of the trace to make your repair, don't even attempt to solder to the corroded areas, skip over it altogether.