Dick Smith Electronics Q-1475 Clamp Multimeter - unit won't zero on AC volts or amps - Repair

Here we have a Dick Smith Electronics Q-1475 Clamp Multimeter with a brand new battery fitted that won't properly zero the display when on AC volts or amps - This multimeter is from the late 90s and if you press down on the the rotary switch the fault will clear so i disassembled it cleaned the gold plated pcb tracks and the rotary switch connector fingers from the old factory lubricant and added some fresh lubricant and the multimeter tests AOK and is ready for another 25+ years of service.