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Suddenly dont work on one mainboard but work at another ?

Posted: 11 Apr 2015 21:35
by 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 ?

Re: Suddenly dont work on one mainboard but work at another

Posted: 11 Apr 2015 22:40
by 1024MAK
That's very strange :?

Mark

Re: Suddenly dont work on one mainboard but work at another

Posted: 11 Apr 2015 23:10
by 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.

Re: Suddenly dont work on one mainboard but work at another

Posted: 12 Apr 2015 20:34
by 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?

Re: Suddenly dont work on one mainboard but work at another

Posted: 13 Apr 2015 17:11
by 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