Solution

I hate having to read everything to get the answer, so here is what worked for me. More detail about relacing the 120N shock absorbers below:

• [SOLUTION] I used the manual method to open the door and HAPPY DAYS, as soon as the door opened the red PC light disappeared and everything came back to life and working.

A bit of context

• After replacing the 120N shock absorbers (simple, see below) I plugged in and tried to turn on the W3831
• Horror – red PC light on front panel, with no other sign of life
• I assumed that while doing the repair, I had sent the machine into some sort of “I don’t know what’s going on” state, and it just needed a “reset”.
• Google gave many varied reasons for the red PC light and I tried various of the suggested solutions e.g. unplug and leave for 5 mins, but no good – red PC light on and otherwise blank front panel
• I had closed the door while everything was turned off and wondered if opening the door would reset things. But it would not open as there needs to be power for the front panel button to work
• A quick youtube for “manually open miele washing machine door” gave many videos including this one https://www.youtube.com/watch?v=szhI1obyNeE (may be a different video for your machine)
• And as noted above opening the door did the required reset.

Replacing the shock absorbers

• Our W3831 has given 10+ years of great service but recently it has started to get very unstable during the spin cycle. In fact it got so bad that the whole machine would move across the floor…
• A quick google and the most likely problem was that the pair of 120N shock absorbers that support the drum had failed
  • And after opening up the machine, using the guide below, that was the case, one had no “absorbing” capability left and the other was on it’s last legs
• I ordered a genuine OEM replacement pair for A$79 from https://retailapplianceparts.com.au/product/miele-washing-machine-shock-absorbers-complete-set-x2-120n-suspension-legs/
• And then followed the excellent guide from Jared Morgan’s, Stuff and Things blog https://www.jaredleonmorgan.net/fix-a-miele-w-3831-shock-absorber/
• A few extra details that I found, that may help were:
  • A few videos/guides suggest that you may not have to remove the front control panel – for my W3831 you DO. There were two screws holding the top of the main front panel, that were hidden behind the control panel.
  • First step to remove the front panel, is to remove the clear Perspex cover. It feels very tough to remove and I was worried it might break. Eventually found that best place to start was with thin flat head screw driver in top right corner.
  • NOTE after removing the Perspex front panel cover, you will see 2 x metal “springs” in the lower groove that are used to push the Perspex cover up – I didn’t notice them and I nearly lost them when they fell out as I removed the main panel
  • When replacing the side panels, make sure you place the lower edge of the side panel under the lower part of the main frame first.
  • Most of the retaining screws are the same BUT a few are subtly different e.g. slightly longer/shorter, with a pointed/flat tip etc. Two specific ones I noted were:
    • Front top control panel – one of the screws is slightly shorter.
    • Main Front panel – there are 2 screws on each side behind the base plate with a small metal bar between them. One of these screws had a flat head, the other was pointed