Suddenly dont work on one mainboard but work at another ?

[Crazyboss]

Hi.
the -06 mainboard I wanted to change the video daughterboard, after that I could not get the computer to boot. I unplugged the Rememorizer, and then put in the original roms and then the computer worked again, I even could load games from tape without any problems.

Then I unplugged the 2 roms and tried the rememozier again, still the same tried the rememorizer on another board where it work as it should boot up in cp/m on the vga output.

So the rememorizer work, but what is wrong here ? Any clue.

When I try with the -06 mainboard, I get black screen and humming sound as expected, but for much longer time than normal, and the vga output shows a yellow flashing cursor.

To me it looks like the Computer do not see the remeorizer at all ?

[1024MAK]

That's very strange

Mark

[Martin A]

Did you have to change the RAM/rom jumpers when you tried it on the other MTX ?

Something you could try ejecting and re-inserting the SD card fixed my re-memorizor when it failed to boot when I hadn't used it for a while.

[Crazyboss]

Martin, nothing was changed, just took it from one MTX to another. Its quite weird, like something was blown.

Maybe an IC controlling the exp. port ? So it dont see any add-on boards?

[1024MAK]

I think what Martin is getting at, is are the two MTX computers the same RAM configuration?
Is the PAL/replacement GAL correct?

With regards to the video daughter board, I don't recall any critical circuits going to it. The only thing I can think of, is it does use the +12V supply. If this is shorting to ground, then the video DRAM chips will not work, plus it will affect anything else fed from the +12V line.

Mark