The switch lug looks like this on each of my two power packs.

Don't switch it away from the Dryfit setting, because you will lose the circuitry that protects against over-charging.

It occurs to me - what model of charger adapter do you have, and what is it rated at?

There are a number of different ones that work, and the designations seem to vary depending on where the flash was sold, but the voltages all seem to be at or near 7 volts.

My 3 charger adapters are designated, respectively, 402.12b, Typ 708 and Typ 728.