Re: broken double hires

[louiss@gate.net (Louis Schulman)]

In <52c8mk$r4$1@mhadf.production.compuserve.com>, 100041.1464 <100041.1464@CompuServe.COM> writes:
>Which parts of my Platinum //e are responsible for the double 
>hires graphics?
>It's not working anymore. Yesterday (maybe last month) double 
>hires was running fine, now the screen is missing the half of the 
>pixels.
>The orig. (small) Apple 80 col/64KB card is ok, I tested it with 
>another _simple_ //e.
>Are there chips in the Platinum to change and so repair the double 
>hires. I think everything else is working fine.
>
>Stephan

There seems to be something missing from your question.  I assume you are
using some video card?  At least on my //e, the standard 80 col card and video
port don't give you double hi-res, you need a video card.

Given that, have you tested the video card?  What kind of monitor are you using?
Have you tested that?

To directly answer your question, double hi-res is firmware that resides in the 
video rom.  That does not seem to be a likely cause of this kind of problem.

What do you see?  When you say the pixels are missing, are they blank?  Do they
work in other modes?

Interesting problem, though.

Louis