1040 STF showing occasional rogue pixels

[exxos]

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 ?

[sandord]

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).

[sandord]

Have you tried a different monitor and shifter chip ?

I tried a different shifter: same story.

[exxos]

have you tried pushing down hard on each ram chip during YAART and see if anything happens.

[sandord]

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.

[sandord]

I also tried a different MMU, no difference.

[sandord]

YAART doesn't show any bad pixels on 512 kb.

[exxos]

Very strange.

You could try diagrom if you can program roms.

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

[sandord]

Very strange.

You could try diagrom if you can program roms.

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

Sadly, no.

[exxos]

I found this program, never used it, but looks like it does some bit tests on screen...

MEMTEST.zip

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