Amiga 3000D won't boot [SOLVED]

[EzdineG]

Hello all!

I have an Amiga 3000D that worked fine when I stored it about 2 years ago.  Yesterday I hooked her up and she wouldn't power on.  When I hit the power button I can see the green power LED flash real quick but then return to it's dead state.  I have a SCSI CD-ROM connected externally and can hear it "seek" when I power cycle the A3000.  No fans, hard drives, etc. actually power up though.

What I've tried to no avail:

1. I've stripped everything from the machine except the daughterboard (I understand it needs this to power on?)

2. Disconnected all peripherals.

3. Tried a spare A3000 power supply I have laying around.

Chances are both of these power supplies are dead but I really don't know how to test them if they're not coming on at all.  I understand you can replace them with ATX power supplies if you have -5v and match the pinouts.  I don't know if A3000 power supplies are "smart" and won't power on without a signal, one that is possibly missing and resulting in both supplies having the same effect.

Any help would be appreciated, thanks in advance!

[EzdineG]

The A3000 PSU has a protection circuit which will shut down if a short circuit or excessive load is placed on it's +5V output. So before assuming you have 2 dead PSU's disconnect the hard and floppy drives and remove any Zorro boards first. If you can get the A3000 motherboard to power up then try the floppy, hard drive and Zorro boards separately.

I've stripped the system of everything except the daughter board to no avail.  Would I be able to jump two pins (bypassing the protection circuit) on the power supply while disconnected to see if it will power up?  That way I can focus on the board.

Thanks!

I wrote this guide which may offer some assistance.

Thanks for the link!  The issue I'm having may supersede most of that article, however.  My system won't power up at all; no drives, lights or anything.  The battery had been previously removed, but had caused some damage beforehand.  Perhaps previous battery damage has the board shorting so the power supply is cutting (as per above?)

I take it you checked to make sure the battery did not leak?

Aye, the battery leaked years ago and was removed.  It is possible it was barely in the tolerances of working when I stored it and not anymore.  I hope that isn't the case!  

Thanks for your replies!

[EzdineG]

Well, damn..  If I unplug either power supply and power them up they run fine.

I guess it's safe to say there's a short in the board.  

Time to start poppin' out chips.

[EzdineG]

Turns out the motherboard is toast.  Applying power shorts the supply, even with all socketed chips removed and nothing plugged in to the board other than the power supply.

Fortunately I have a spare motherboard, unfortunately battery damage destroyed the integrated scan doubler years ago

Thanks to all for the help.