Check for juice in the connector(s) too. Juice CAN (but doesn't always) create a bit of a "short"... or more like "an additional atty/carto" added to the connection, theoretically. All it has to do is bridge that little silicone doughnut... on either side (PV or atty/carto). Clean both out well. Usually wiping the threads+end on the carto is sufficient. But the PV's side is recessed.
Get good batteries too. IMR (or protected if allowed for that make/model... maybe not due to it being a booster).