I have acquired a Telwin 140 inverter the fan runs but the lights on the fascia don't light up and it doesn't weld. The previous owner said that when welding it would occasionally lose power and stop. Then one day it stopped. Can't get any info from Telwin as it's badged as an aire inverter 140 and has no serial number on the Telwin plate and Aire don't seem to exist. I wondered if the thermal cutout is faulty. Any ideas anyone? Thank you. parvenu.