Date   : Sun, 15 Apr 2012 20:00:54 +0000
From   : jackleather@... (jack leather)
Subject: MODE 7 video corruption

Hello. i have a disk interface-less model B here. mode 0 - 6 are fine. 
mode 7 displays the symbol below the ? (underscore?) in a random snow 
like pattern. 

Video link of the problem below;
http://www.youtube.com/watch?v=PAc4IGg6KEo


I have replaced IC14 but that made no difference.


A post from last year said;
"The teletext chip may be serialising random junk due to having its inputs
floating. If you plug IC15 back in and check what characters are displayed in

mode 7 when the screen is supposed to be clear, this may give a hint as to
which bit or bits are having problems."


Is there any relationship? what should i try next?

Regards