Conference 7.286::atarist

    Sounds like your Line Output transformer might be wonky. Can you
    see if there's any arching or smell. Switch the lights off as you're
    looking but DON'T GET TOO CLOSE!!!
    ...howard

Sounds like the original problem was the failure of the infamous thermistor
that is prone to die. They may have fixed it, but the fix and/or new
thermistor may also be failing. You could buy some from Best Electronics
and replace it yourself. Or, you could put a meter across the suspected
thermistor and monitor it. If its voltage jumped when you noticed the
glitch, that would mean the thermistor was intermittant (and definitely
the problem).

I've extracted some articles on this common problem from USENET mailings,
and can post them here if you wish.

re .2

>	I've extracted some articles on this common problem from USENET mailings,
>	and can post them here if you wish.

Sure would appreciate that !!

	I seem to be having a bad time with my Atari right now, not only my disk-
	drive seems to reject diskettes that never caused me any problems, I
	notice something similar to .0.
	Booting the machine is OK, using applications to, ( all this only when the
	floppy-drive's not having his hard times ) but then, without any cause or
	warning, it seems the *physical* screen is disrupted. It looks like this:

	 Normal screen		 Disrupted:
	---------------		..==--==--==--==--
	|             |		| ==  ==  ==  ==  |	(Both screens same
	|             |		| ==  ==  ==  ==  |	 dimensions, btw:-)
	|             |		| ==  ==  ==  ==  |
        ---------------		..==--==--==--==--

	In the above picture, the dots (..) indicate a double intensity bar, 
	outside	the normal screen, ie. where the black border should be.
	The == indicate a black bar on the screen.
	Whenever this situation occurs, mouse actions and software output are
	displayed and handled correctly, though crunched in the remaining
	display bars. Occasionally, a short blip on the screen shows a completely
	black screen with a fading cathode-ray and then back to the situation
	above.
	Does anyone recognize this behavior ? What have you done with it ?
	At first I thought of some sort of bad synchronization, but the fading
	ray maybe points to some sort of power failure ?? I did check all the
	power cables, and the ST-SM125 connection.
	Can there be any relation between this problem and the atop mentioned
	disk-drive problems ??

	Please, if you know how to get rid of this, without simply buying a new
	ST (or: Mega ST) plus monitor, reply here, or mail me at UTRTSC::TEYEMA
	for I am planning on taking the complete set to the service-centre this 
	weekend. That will probably cost me some guilders (Dutch currency).
	


	Lotsathanxinadvance,

		Casper A. Teijema (they got my name misspelled for my VAX account,
				   so that is utrtsc::teYema)

    Thanks for the replies. Please post the thermistor articles when you
    have the time.
    
    Thanks,
    Dave.

    I just phoned the shop to see how they're getting on with my monitor.
    They claim they are not seeing the screen 'glitch' - claim they've had it
    on the bench for an hour or so a couple of times and no sign of anything !
    Looks like there's two possibilities : 
    
    (a) Repair shop is incompetent (not to be discounted). The glitch is
    easily missed if you're not staring right at the screen when it happens. 
    or 
    (b) Problem in ST is causing glitch.
    
    I would have thought (b) was unlikely - anyone know if it's possible ?
    
    Dave.
     

    I too have noticed a subtle problem with my mono monitor. I have
    the option of changing the screen (black on white or white on black)
    within the terminal emulator program I use. If I make the background
    black (meaning white letters) the brightness changes with the number
    of characters being displayed. Very few letters and the letters
    are much dimmer. Lots of letters will cause the individual letters
    to be much brighter!!!! Wierd huh ??? If a scroll a bunch of text
    onto the screen and let it set for a few seconds the screen will
    gradually get brighter as I set and watch it.
    
    Anybody got any ideas????
    
    Al
    

I may have spoken too soon, since the notes I have deal with the SC1224
color monitor. But I vaguely remember that there was a thermistor problem
with the monochrome monitors as well. Anyway, here's some info I collected
regarding the thermistor problem:
=============================================================
A Blown Color Monitor
---------------------
Apparently the Goldstar version of the color monitor, SC1224, has some
reliability problems. Rick Mills offered this insight:

  I have a friend who recently was given a SC1224 monitor
  only to have it breakdown a week or so later. This one was made by
  Goldstar, so I have my doubts about getting any OEM parts for it...

  Here's what it is: On the power supply board there's what
  looks like a thyristor that's blown apart - it's labeled 'TH901' on
  the board. It's right behind the fuse.

Another reader added the following:
 
  The TH901 is GoldStar's most famous part to blow, apparently.  Call 
  GoldStar.  They cost about $5, I think.  Get two in case there's something
  else wrong in addition and it blows the first one when you replace it.

 
Finally, Rick Mills summarized the comments he received:
 
        I wanted to summarize the messages I recieved concerning
  the problems with my friend's SC1224 (Goldstar) monitor, but rather
  than page through the horror stories, let me offer what looks like a
  solution - 
        There's a company called Best Electronics in the 408 areacode
  of california (San Jose, Sunnyvale) that carries just about anything that
  they can get a hold of having to do with electronic problems (with Ataris).
  Mouses, keyboards *and* the infamous thermistor (Labeled TH901) on the power
  supply board inside the monitor that has conspicously blown on quite a few
  SC1224's...
        So for those with dead Goldstar's who have determined that parts
  are unavailable - give these guys a call!
 
	Best Electronics - (408) 243-6950
 

    
    RE the base note.
    
    
    Dave-
    
    
    My mono monitor is displaying the same symptoms, i.e. every few minutes
    the screen blanks with a white squiggle in the middle and then springs
    back into life. Its just as though its been turned off and on quickly. 
    
    I have checked the external connections, but have not yet got inside.
    
    Did you ever find out what was wrong with yours?
    
    Has anyone else had and fixed this problem?
    
    (I am only being lazy, I will have to get inside it this weekend and I
    want to save myself some time if possible!)
    
    Cheers
    
    Pat K.

Pat,

well the shop (ComputerCare South) never managed to fix the problem. I've been
using the thing a lot of late and the problem doesn't seem so bad as I remember
it (every 5-10 mins or so)- in fact I hardly notice it .(I've probably been 
conditioned to ignore it by now). If you ever find out what the cause is I'd 
love to know.

Dave.

    Well, well, well,
    
    I have come to exactly the same conclusion, since the flash doesnt seem
    to cause any software to crash, I just live with it.
    
    However in the back of my mind lurks the sure thought that one day in
    the middle of some critical work, perhaps my son's main coursework, the
    monitor will roll over and play dead for ever!
    
    Because I cannot duplicate the Atari environment, (I dont want to buy a
    second ST system), and there is nobody I know who can provide a
    temporary relief system, I have bought a I*M PC clone system. If I need
    to get work done, there are four pc's within 100 yards of my house.
    
    I still have the ST, and I stll think its a lot superior!, but she who
    must be obeyed is getting pi**ed off with two systems, three monitors
    etc etc in her lounge!, so eventually the ST will have to go. SOB SOB
    
    Cheers for now 
    
    PAT.