STE issue: works in B/W hi res but not TV or colour monitor output

Troubles with your machine? Just want to speak about the latest improvements? This is the place!

Moderators: Mug UK, Zorro 2, spiny, Greenious, Moderator Team

Post Reply
Chandler
Atari God
Atari God
Posts: 1416
Joined: Tue Feb 14, 2006 12:15 am

STE issue: works in B/W hi res but not TV or colour monitor output

Post by Chandler »

I have an STE which works fine in high res, however if i connect it to either a TV via the RF port or colour monitor via a 13 pin scart cable (tested 2 of them) then the screen is black and dark

What happens is as soon as i switch on the STE i can see briefly the white screen appearing as it boots. Then as soon as the orange floppy LED illuminates, the screen goes dark, also there is no sound either in these modes but there is sound and picture in high res mode

Does anyone have any idea what this could be? :)
User avatar
1024MAK
Atari Super Hero
Atari Super Hero
Posts: 652
Joined: Sat Aug 01, 2009 2:58 am
Location: Looking forward to summer time in Somerset, UK...

Re: STE issue: works in B/W hi res but not TV or colour monitor output

Post by 1024MAK »

Not sure if this exactly matches your symptoms, but the monitor DIN socket uses an input on one of the pins to detect which type of monitor (if any) is in use. If there is a fault on this input circuit, the computer will only work in the high resolution mode.

Mark
Falcon, Atari 520ST, 520STFM, 1040STE, Mega, TT and more PC's than I care to count and an assortment of 8 bit micros (nearly forgot the Psion's).
Visit the Atari-Forum Wiki. Lots of technical info at DrCoolZic Atari ST Site :D
kolli
Atari nerd
Atari nerd
Posts: 45
Joined: Sat Jul 23, 2016 7:37 pm

Re: STE issue: works in B/W hi res but not TV or colour monitor output

Post by kolli »

1024MAK wrote:If there is a fault on this input circuit, the computer will only work in the high resolution mode.
Pin 4 has to be grounded to switch the machine to monochrome hi-res. The 'circuit' for this is in the monitor plug: pin 4 and pin 13 shorted. So, I can't imagine a Situation where pin 4 would internally get shorted out of a sudden.
Chandler
Atari God
Atari God
Posts: 1416
Joined: Tue Feb 14, 2006 12:15 am

Re: STE issue: works in B/W hi res but not TV or colour monitor output

Post by Chandler »

I have seen this problem before but the other way around. ie: no high res but colour ok and that was the U405 IC

Just wondering if this could be the cause again again this time? or even the MC 1377P?
Chandler
Atari God
Atari God
Posts: 1416
Joined: Tue Feb 14, 2006 12:15 am

Re: STE issue: works in B/W hi res but not TV or colour monitor output

Post by Chandler »

REPAIRED! it was U405 IC :)
Post Reply

Return to “Hardware”