Page 1 of 1
Atari STe video switching color/mono
Posted: 11 May 2020 13:09
by nemox
Hi,
my atari 520 STe can't switch to color mode. switching mono / color mode does nothing, the computer does not even restart.
Pls any idea?
Re: Atari STe video switching color/mono
Posted: 11 May 2020 13:16
by rubber_jonnie
How are you switching it?
The ST and STE are switched depending on the type of cable that's plugged in.
So either you are using a Mono cable, a colour cable, or a VGA switcher.
Please expand on how you are trying to change mode.
Re: Atari STe video switching color/mono
Posted: 11 May 2020 14:00
by Smonson
I had a problem like this once on my STFM. The mono-detect pin in the video socket is sensitive to static electricity and can become damaged, and then it doesn't do anything anymore. It's connected straight to the 68901. I had to replace my 68901 with a new one to fix the issue. As far as I know it's the same setup on an STe.
Re: Atari STe video switching color/mono
Posted: 11 May 2020 16:40
by czietz
Smonson wrote: 11 May 2020 14:00
I had a problem like this once on my STFM. The mono-detect pin in the video socket is sensitive to static electricity and can become damaged, and then it doesn't do anything anymore. It's connected straight to the 68901. I had to replace my 68901 with a new one to fix the issue. As far as I know it's the same setup on an STe.
In the STe, it's not connected directly to the 68901 but to a 74xx logic IC. That one often dies, as well, though, and is the most common cause for what
@nemox is observing. Please see this long thread incl. happy ending
http://atari-forum.com/viewtopic.php?f=15&t=38424, also as a cautionary tale to replace the IC with the
exact same part number.
Re: Atari STe video switching color/mono
Posted: 11 May 2020 17:25
by stephen_usher
Or faster version, e.g. 74ASxxx (though that is CMOS so your milage may vary).
Re: Atari STe video switching color/mono
Posted: 11 May 2020 21:13
by nemox
Thanks
.I'll test the circuit 74xxxx