exxos's Atari, Amiga & retro forum

olivier.jan wrote: 26 Jan 2022 10:32 Sorry if this sounds stupid, but did you check the motherboard jumpers are set correctly for the type of ROM you’re using ?

Yep, one of the first things I did and verified the ROMs worked in my own STE with the same jumper settings.

FWIW, I toasted the GSTMCU on my STE (don't recall at this point how) and also had just a white screen and no diag cart boot. I got a new one from atarifreakz on evilbay. The replacement was surprisingly easy, considering I'm not super comfortable with my SMT skills. I used low temp solder to pull the old one off and then drag soldered the new one on, and it worked first try. (Not sure I would succeed again, though. Maybe I got lucky!)

So, if your diagnosis does end up pointing you to the GSTMCU, all is not lost!

derkom wrote: 26 Jan 2022 10:43 FWIW, I toasted the GSTMCU on my STE (don't recall at this point how) and also had just a white screen and no diag cart boot. I got a new one from atarifreakz on evilbay. The replacement was surprisingly easy, considering I'm not super comfortable with my SMT skills. I used low temp solder to pull the old one off and then drag soldered the new one on, and it worked first try. (Not sure I would succeed again, though. Maybe I got lucky!)

So, if your diagnosis does end up pointing you to the GSTMCU, all is not lost!

Cool, thanks, nice to know, but hoping it won't come to it!!

Ok, so it seems that the Blitter issue was affecting things, I've done a new LA capture of all the ROM address lines plus /CE, and it seems that A1 and A2 are not playing nicely.


A1 should go low 2us after the rest go low, so I will take a closer look at both A1 and A2 since neither are doing as expected.

A2 should go low at the same time as the rest.

Channel 0 is /CE, so that seems to be good again.

I can at least focus on those two and when they are working look at what's next.

I still potentially need to do what exxos and Stephen suggested, but this will do as a start.

If I can get both address lines to play nice and it still doesn't work, then I can look at the data lines.

So, now the search for the missing bits. :-)

Start at the CPU and go from there?

stephen_usher wrote: 26 Jan 2022 12:54 So, now the search for the missing bits. :-)

Start at the CPU and go from there?

Yeah, I'm going to trace it through the schematics that Sporniket did, as if I keep it to just the top and bottom layers, I can trace every step of the way and make sure every last hop is good by buzzing them all out.

I'll look see everywhere they go, CPU included, to see what's what. At least it's narrowed down to just those 2 address lines for now.

I'll class this as progress :)

Look closely, in case you can see the missing bits fall onto the carpet. ;-)

stephen_usher wrote: 26 Jan 2022 13:48 Look closely, in case you can see the missing bits fall onto the carpet. ;-)

:dizzy:

I can see the headline: "Squid like creature attacks Atari STE"

I've enjoyed watching this journey. Really been an eye opener to see what can be done with the proper equipment. Look forward to seeing more! Looks like your making some progress at least looking at those pics from the LA.

Regards,

Brett