These issues are tough because it sounds like something is touching something it shouldn’t when the playfield is lowered, yet it is hard to see because you can’t look inside with the playfield lowered. Here’s a potential idea that could help:

In the manual find all the things running off of that fuse. Then with the playfield lowered and power OFF put your camera on video mode, stick your hand in through the coin door, and slowly record a video aiming up. Move your camera slowly along the areas connected to that fuse, along the rails in the cabinet, along the lock bar, etc. Then take your phone out and play back the recording. Pause it and try to go through it frame by frame zooming in on the various areas. See if you can identify anything making contact that shouldn’t be.

This helps. Check for things touching those tabs and the lock down bar when the playfield is closed.