Are you sure your power supply is OK (Test it with a multimetre). I did not read the other thread.
Strip the Amiga down.
Disconnect the floppy, all external devices, modulator. Until you have just the motherboard left. Make sure the ROM and 68000 are seated ok.
From the phono mono video socket on the back connect this to the Video in (scart / phono) on a TV
Most modern TV's have these. Put the TV on the External video source channel you have the amiga input to.
Switch on the PSU. After what seems an age (minute or two) the Amiga will realise that no floppy disc drive is attached an will drop to the kick start screen.
If after 2 mins this doesn't happen I'd pretty much say your mobo or psu has a fault.
