Amiga External Flicker Fixer on Amiga 4000?

[LoadWB]

Looks like the same one I got a good 15 years ago or so.  Has worked on every Amiga I have: 500s, 1000, 1200, 2000, and 4000D.

[LoadWB]

I've just plugged it in now and turned machine on.  Both the lights on the flicker fixer are operational with the green (FF-Mode) light flickering.  The message on my LCD is "input not supported."  I will wait a few minutes and see how it goes.

You could be running into the same problem I ran into the past couple of days with my PIV: the input to the device may already be 31kHz.  Do you know what your 4000's screenmode is?  I also have a Cyberstorm MK III which has a "No 31kHz" setting for bootmenus which apparently does not work.