Amiga 4000 problem

Answer 1

Sounds alot like bad power supply unit (psu)

The first thing to do is check with a multimeter about volt rates you need atleast 11.4v on plus (+) and minus (-) if is lower, you can be lucky it will show something but not run stable, but need new psu a good power good signal 5v (+) my psu at the amiga this wired is brown, that was my problem with 1 scsi cdrom and scsi harddrive and a4091 scsi controller, picasso iv grafichscard and x-surf network card. (my psu did 11.42v (+) on the 12.05v (-) I had the normal a3640 card as processor card, and floppydrive too.

Use the six pin on motherboard and use the multimeter or even better disconnect all stuff and test psu alone with multimeter.

I think I made a mistake myself, because I would try have an old at psu but think I screwed myself up with 5v (-) and power good 5v (+) so i think my motherboard is burned off I just need maybe change the lisa chip, no screen but can see lights on leds, my brown just gives me around 1.5v-1.7v (+) atm.
Which needs to be close to 5v (+) on the power good.

You can also have bad roms on u175 and u176.

If anyone can help me on this too it would be good, just email: [e-mail]

hope this info help you in someway.