LG washer dryer won't spin at full speed?

[Vjkdigital]

Hi all, WD1435RD washer dryer combo, rated at 1400rpm spin, but only spins up to 800rpm (as reported when SPIN button held while spinning). 

I have the service manual and have entered service mode to test spin there, and it spins fine at 1400rpm from there, but not during a cycle or when set for spin only. Water level sensor frequency comes up as 255, manual says it needs to be above 248. As I expect it would not like to spin at full speed until the tub is completely empty. 

I generally do all my own repairs on this machine but this one has got me stumped. I suspect there is a sensor out of specs somewhere that's telling the main not to use full spin speed. I've also tested at no load to confirm machine is not overloaded. 

I'd appreciate any help as a call out is just too expensive for me on a low income. 

Thanks 
Kym (new member) 

[Whitegoodshelp (Andy)]

Which wash cycle are you using? Only cottons is likely to do the top spin speed. Other wash cycles are likely to spin slower. Some option buttons might also reduce the top spin speed. Another thing that can prevent the top spin speed is if the laundry is not perfectly balanced. Sometimes if there is no laundry in the drum it won't do the top spin either.

[Vjkdigital]

Using cotton cycle. One in five spins you can hear it spin up to 1400, the other four spins at 800, it's not overloaded as I've tried it with no garments at all and although it's showing 1400 it still only gets to 800.

[Whitegoodshelp (Andy)]

Some will only do full spin with a load in and only then if it’s perfectly balanced. Under loading is more likely to cause out of balance than overloading. The fact that it seems to do full spin sometimes but not others could mean it’s not managing to perfectly balance some loads. Either that or it’s a very tricky intermittent fault.