Hotpoint WT940 – Wrong Pump?

I have a Hotpoint Wt940 Washer which is only 3 weeks out of it’s 12 month warranty 🙁

Started making a burning smell and after investigation found that there were hair grips in the pump and they had caused it to burn out.

So I took the pump to my local spares shop, showed the owner the pump and he sold me a replacement for £15. Bargain I thought. Although the pump had a slightly different live / neutral connectors I was assured it was the right one.

I got it home and connected it up and the machine worked fine for 3 cycles. On the 4th a burning smell started as the pump went into overdrive and kept running almost from the start of the cycle. It was pumping the water out as fast as washer was filling. Also pump will only stop when the machine is turned off at the mains. If the machine is turned off using the switch on the front it still runs.

Engineer was out today and after I told him the symptoms he suggested it was the wrong pump and it has probably broken the motherboard. He is off to get me a quote for a replacement, but warned me it would be expensive.

Does this diagnosis sound right? Seems strange that the pump would not simple cause the motherboard to fail completly rather than cause a fault.

Should I go with a replacemnet board, or is it better to put it down as a bad job and get a new machine?