No juice to Drain pump on Samsung WD8704RJA

Hi there, long time browser, first time poster here.

My trusty Samsung WD8740RJA finally developed a fault yesterday (error code 5E, drain problem) and being a bit of an amateur fiddler I thought I'd have a go at diagnosing the problem before calling in the professionals. I went through the very helpful default troubleshooting guide on here but still need some help. This is what I've done so far:

The drain pump isn't activating at all but I checked the drain hose and filter were clear first anyway, no probs there. I then took the drain pump housing out and verified there were no blockages there either, the impeller on the motor is spinning freely.

Next, I checked the motor itself. No visible signs of wear, no burn marks or nasty smells or anything and a resistance test gave a solid 171 ohms so I think that means the motor is fine. I then turned my attention to the power supply to the motor and there I think I saw the problem. A meter on the terminals show 37v at machine power-up but this only rises to a maximum of 88v when a drain cycle is run, dropping to 64v after a few moments. This remains constant until the cycle is cancelled and it drops back to 37v. As far as I can tell, it's a 240v motor so I'm assuming the supply is the problem here.

I'm a bit lost beyond this point, I'm not sure what component supplies the power so am not sure if this is easily fixed or if we're talking an expensive part needed. If so, this is a 4-5 year old machine (from memory) so am assuming it might be better to replace rather than repair.

Can anyone suggest what this might be and how much it might cost to repair?

Cheers muchly in advance!