There are many versions and makes/models of plug and play trolley type systems. We do repairs and maintenance on most of them. Sometimes the units require inverter head replacements or repairs. Please see options below. If you are not sure what your unit requires, please contact us or bring it in for assessment and we can provide a quotation to repair or replace the inverter head. NB: We do have a minimum charge should you decide not to proceed with any repairs. You can also book a call out for us to come to you for these repairs.