Thanks Doddy,

Before I get too involved, I have a couple of things to try. I always print using the SD card and a faulty reader could be the cause, so first I am going to try printing via the USB link. Also I will get a new card reader from Wanhao UK on a return basis. If no difference, it can go back. The same for the mainboard, but I may end up sending that to them to check out in another 4DS machine

Sticking a finger on components is difficult as they are all under the main deck and difficult to access when the machine is running.

I thought about the PSU glitching, it is a 24v SMPS unit, so I might just put some sort of voltage drop detector on it using my little scope, but that would be a pain and so is down the list.

Likely suspect is the card reader or the cable from the reader to the mainboard, I had trouble with it before as it got sh1t in it, so maybe the pins are messed up.

I haven't got £150 to shell out on an off chance anyway, so I would have to be damn sure first.

Cheers,

Rob