Date   : Mon, 28 Nov 2005 19:05:53 +0000
From   : Mike Tomlinson <mike@...>
Subject: Re: BBC B black text in Mode 7

In article <002301c5f410$1e3856f0$0201a8c0@...>, John
<blip@...> writes

>    Types OK, have visible text in other modes. Cannot change text 
>    colour in Mode 7.
>
>    Never seen this before - any ideas please?

It's almost certainly the VIDPROC, ic6.

Does it have a heatsink?  

Does it get warm? 

Can you substitute the _identical_ chip from a known working machine?
i.e. if the chip is a Ferranti 9C ULA, change it for that only; if it's
a VC202x chip, change it for that only.

Check the big 2W resistor (R114) next to it is soldered in okay and not
broken. 

Change the position of link S27 next to the VIDPROC with the power on -
does anything happen to the screen? Does it fill with white squares, or
does it show correct video, but inverted?