exxos's Atari, Amiga & retro forum

Its actually ST4.4 diag cart and I can't find any description in the manual about I1 errors.

Will try Diagrom and see if that gives us some more insight

ahhh ok, so likely its writing all zeros but reading 1 back I would assume. So either the address isn't being driven somewhere, or its shorted to 5V somewhere.

And that's the bit I cant find. As I say, the right 0s are D0 to D15 burnout sure about the left lot unless they are address lines. But if so, A0-A15 seem ok as well

Would assume its dataline 1 (bit 1) which is stuck high.

Ok, so they are both data register bits. Fixed D1 on the left 4 falcon ram chips, now D1 on the other side playing up, LOL. Time to check my soldering

1 new ram board required. Haven't got any more SMT ram and can't be arsed to remove the chips again.

I did find a lifted track underneath one of the ram chips but fixing that has now given me a I2 ram disturbance.

So time for a new ram solution. Two steps forward with this one but one step back.

It's having a difficult birth this Alpha board but born it will be, dragged kicking and screaming into the real world (well hopefully anyway)

And another step sideways, LOL.

I've just tried turning the Alpha on today and I actually get a garbled menu for the diag cart. Pushing the relevant buttons carries out the relevant tests as far as I can see at least but the monitor screen stays a 50hz black, LOL.

what do you all think of this?

I've put Diagrom into the Alpha and I get a bit better serial output but still no video. It does let me check the memory out and surprisingly it passes, have tried 3 times now as I didnt believe it.

I'm now wondering if the lack of output is something wrong with the shifter, so I'd better go look for another one if those.

And...............

ITS ALIVE!!!!!!!!
Sorry the pic is a bit crappy, I've got a loose connection on the video by the looks of things

:cheer: :cheer: :cheer: :cheer: