Page 4 of 11

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 15:39
by exxos
sandord wrote: 28 Sep 2018 15:22 RAMTEST says 171 OK passes, 0 fails.
:roll: Do you see the bad pixels on screen currently during the test ?

Have you tried a different monitor and shifter chip ?

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 15:45
by sandord
exxos wrote: 28 Sep 2018 15:39
sandord wrote: 28 Sep 2018 15:22 RAMTEST says 171 OK passes, 0 fails.
:roll: Do you see the bad pixels on screen currently during the test ?

Have you tried a different monitor and shifter chip ?
Currently, I'm at 623 OK passes. No bad pixels to be seen anywhere.
We've had this ST connected to three different monitors, same story everywhere.

I'm going to try with another shifter in a minute but I doubt that'll make any difference since the bad pixels stay bad as long as nothing writes to the the RAM at that spot. I don't think even the worst shifter could do that, render a specific pixel wrong over and over again.

Oh, I wanted to add that the bad pixels never flash (unless they're on a screen that is swapped by the program, like most games).

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 15:55
by sandord
exxos wrote: 28 Sep 2018 15:39 Have you tried a different monitor and shifter chip ?
I tried a different shifter: same story.

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 16:07
by exxos
have you tried pushing down hard on each ram chip during YAART and see if anything happens.

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 16:34
by sandord
exxos wrote: 28 Sep 2018 16:07 have you tried pushing down hard on each ram chip during YAART and see if anything happens.
I just tried it on all chips of bank 0 (bank 1 is still disconnected). No errors.

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 16:34
by sandord
I also tried a different MMU, no difference.

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 16:52
by sandord
YAART doesn't show any bad pixels on 512 kb.

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 17:03
by exxos
Very strange.

You could try diagrom if you can program roms.

https://www.exxosforum.co.uk/forum/viewt ... =50&t=1201

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 18:22
by sandord
exxos wrote: 28 Sep 2018 17:03 Very strange.

You could try diagrom if you can program roms.

https://www.exxosforum.co.uk/forum/viewt ... =50&t=1201
Sadly, no.

Re: 1040 STF showing occasional rogue pixels

Posted: 28 Sep 2018 20:06
by exxos
I found this program, never used it, but looks like it does some bit tests on screen...
MEMTEST.zip
Blank_00027.png