Dyson Outsize cutting out

My Dyson Outsize is cutting out after just a few seconds of running. At first, it would do this once or twice then run fine for the remainder of vacuuming the house. Now it's continuously cutting out. Swapping batteries, using different cleaning heads, cleaning the filter, checking that side port in the bin haven't resolved this. The mechanism between the switch on the main body that presses the switch on the battery appears to work OK. Dyson's answer was to replace the main body for $329 - more than the cost of a complete refurbished Outsize.

Any help is appreciated!