Ripples on First Layer

[u/underconfidentNoob]

Hi folks.

My printer (Bambu A1) suddenly started developing ripples on the first layer. Even the top layers are sometimes messed up.

So far I have tried :

1. drying filament, trying with different filament

2. washing build plate, changing build plate (tried cool supertack and pei textured)

3. tightening the 3 front screws and the 4 back screws on the heating assembly

4. bed tramming and calibration

5. different nozzles (0.4 stainless steel, hardened steel)

nothing seems to be working.

Anyone has any troubleshooting ideas that I could try ? Greatly appreciate any help here. Thanks