Re: CRT TV as monitor working backwards

[Patrick Schaefer <pa.schaefer@web.de>]

Am 09.08.2012 07:48 schrieb KP:

> Is this normal?

Yes and no. In color mode, the IIGS generates a PAL or NTSC color signal 
with chroma and luma information. In BW/text mode, the signal does not 
contain any color information and no color burst. Usually a TV decides 
based on the color burst whether it gets a black/white or colour 
transmission. In BW mode color processing is shut down to prevent color 
fringes.

Today's digital flatscreens are not used to receive BW TV transmissions, 
at least not in civilized countries. Even if you watch an old BW movie 
it is still a color transmission (with a colored station logo in the 
corner). Therefore this color killer circuit is sometimes not 
implemented anymore.

If this is the case with your TV you'll get the fuzzy BW picture with 
any BW source. Try an old CCTV camera or another computer.


If the problem occurs only with this one IIGS, its burst generation 
circuit may be faulty. There should be no burst in text mode.


Patrick