On the back of my Sterling Power Products inverter repair (https://fixitworkshopblog.wordpress.com/2017/04/07/sterling-power-products-pure-sine-wave-inverter-repaired/) a customer enquired to see if I could repair his faulty inverter.
The customer’s inverter had been connected up properly but had been severely overloaded and it would appear that the protection modules within the inverter had not operated correctly. Therefore a burning smell had been reported, just before final failure.
This was going to be a difficult repair as I had no schematic diagram for the main PCB and I was effectively going to be testing components in isolation using rudimentary methods.
A quick look around the inside of the unit revealed no obvious damage, but upon testing the IBGT transistors on the units’ high voltage output and several Zenner diodes in line with them, revealed serious damage to that part of the circuit.
These components are not cheap and collectively, the cost in parts alone would have been over £50, without my time factored in and without the guarantee that the unit would work again. On that basis, sadly, I had to inform the customer that the unit was beyond my help and probably beyond economical repair. It will therefore be disposed of responsibly at our local amenity tip.