[DirtyLaundry]

Just to show you the main board in full.

You can see a thickish black cable beside the resistor ( which is 33 ohm and labelled R2, this was replaced by QER). That cable is ( I think) what should carry current to the small board. But there is 0v at that cable.

When I test the pins on the back of that ribbon cable you saw on the small board I get 39v dc where it should be 16v and I get 0v where it should be 5v. There is a GND connection as you said on the first pin.

The problem is that even if I found another faulty component it would have to go back to QER to repair. Another £55

Im at the stage where I will buy a new control board ( I’m loathe to scrap the whole machine) but just want to make sure there isn’t something else that will damage it. All I can see prior to the board is the mains filter which has 240v output. Could there be something faulty “downstream” of the control board which will damage the new board?

Or can I replace the control board with any confidence that it will sort the problem?

[DirtyLaundry]

The replaced chip is bottom right.

Original was
LNK304GN

Replacement
LNK304PN

datasheet shows the difference is just the packaging.

[DirtyLaundry]

Thanks Dave.
There is a connector clips onto the large board from the mains filter. and I measured 240v ac on that, so board has power and I picked up 240v at several other points on that board ( there are some large “blocks” on that board). However it does not make it as far as the R2 resistor (33ohms) which is connected via a cable to the small board ( the LNK chip and on/off switch are on the small board).

A ribbon cable also connects the large and small boards. Though labelled 16v on one pin, I measured 39v dc there. That voltage was steadily dropping.

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