Amiga 1000 Diagostics

[HolySamosa]

Recently scored an Amiga 1000 that externally and internally looks great.  Super clean!

However, when I power it up I get the following behavior:

1 - Black screen for approx. 4 seconds
2 - White screen for 1/2 second w/ four (i think) flashes of the power LED
3 - goto 1

Any suggestions?  

Thanks!

[HolySamosa]

Thanks for the suggestions, guys!  I tried removing the RAM expansion with no effect.

Will try reseating the ICs this weekend.

[HolySamosa]

I've now reseated all of the ICs and the CPU.  It looks like none of the ICs on the daughterboard are socketed, so I didn't remove it.

I also tested the voltages from the power supply and compared to those listed in the "A1000 Assembly Level Repair" document.  Voltages were as expected (well, I did read ~12.1v and ~5.2v, but I assume this is within tolerances)

Same behavior. :-(

[HolySamosa]

Thanks!  Will do all of the above, but it will have to wait a week.  The Amiga 1000 and several of my other vintage computers just went on display for the week at a retro-tech exhibit at our university library. :-)

[HolySamosa]

Okay, I'm back at it.

I tried swapping out for another set of CIA chips I had handy-- no luck, same behavior.

Also reseated the daughter board and again the ICs while I was at it.

The motherboard is REV A 327049-01.

There are no modifications that are obvious to me and no boards installed other than the 256k ram expansion.  No sidecar.

I do have a working Amiga 2000 that I could perhaps borrow parts from for diagnostics.

[HolySamosa]

Here are images of my motherboard and daughterboard: