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Conference 7.286::atarist

Title:Atari ST, TT, & Falcon
Notice:Please read note 1.0 and its replies before posting!
Moderator:FUNYET::ANDERSON
Created:Mon Apr 04 1988
Last Modified:Tue May 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1433
Total number of notes:10312

1330.0. "Vt240 colour monitor connection!." by HEAVY::TAYLOR (Steve Taylor) Tue Nov 03 1992 15:54

    Hi 
    	I have my Atari hooked upto a colour VT240 monitor and it works
    fine appart from the fact that it doesn't use the whole of the screen.
    I've been told this is due to the fact that the VT240 monitor is an 
    'Overscan' monitor!. A friend told me that it was possible to open up
    the whole of the screen by using a program called : Overscan.prg. This
    I have tried, but running the program seems to have little effect!.
    
    	Can any of you experts out there throw some light on the subject?.
    
    
    Any help appreciated.
                      
    	Regards Steve.
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1330.1my experiencesBERN01::RUGGIEROMarkus from SwitzerlandWed Nov 04 1992 04:5523
    I once tried a VT240 tube on my MegaST and it worked fine.

    There was a hack from a german magazine (STmagazin) that allowed to
    mess with the internal timing of the MMU and video shifter so that more
    RAM was read out during a video scan and thus the black borders could
    be used for display also.

    A later version of this overscan.prg came together with a little
    hardware that gave more stability to these opened time frames. This
    thinggy allowed me to have over 30% more pixels with the VT240 tube.
    Tried other monitors and did achieve different results. It depends very
    much on the particular model. My SM125 goes for only about 15% more.
    Sorry can't remember the actual numbers (hor by vert).

    This overscan hardware/software combo does not work with TOS above 1.4.
    From ads I learnt that they offer a TT version but I did not upgrade so
    far. (Anyone out there who knows if this version would work with SST030
    and TOS2.06?)

    Have a nice day


    ---markus---
1330.2RE : -.1HEAVY::TAYLORSteve TaylorThu Nov 05 1992 19:4111
    
    Thanks for the input!, sounds encouraging!. From your reply it looks 
    as though the overscan program works in conjunction with some type
    of 'bolt on' hardware!. By the way, my system is an STfm with 520k mem;
    about two - three years old!.
    
                       Any further input appreciated.
    
    	Cheers STeve.
    
    Ps: My my version of overscan could be crook!.
1330.3OverSan with VT240 and TOS 2.06COL01::SELLWed Nov 11 1992 07:3523
I tried a VT240 tube with my MegaST2 with TOS 2.06 and it worked
fine. 

I use OverScan in the german version 3.0zg. I installed the kit
in about half a day by myself. You have to interrupt some paths
on (and even some under) the PCB. You get a plug to use the ST
without the hardware enhancement, but I never used it.

You can choose during bootprocedure wether to use OverScan or
not. There is an editable startupfile in which you put the names
of programms, which are not able to use the higher resolution. 

I updatet the OverScan software, when I changed from TOS 1.04 to
TOS 2.06 

With the monitor of a VT240 I get resolutions:
	LOW  60 Hz 416 * 240
	     50 Hz 416 * 280
	MID  60 Hz 848 * 240
	     50 Hz 832 * 280
	HIGH 70 Hz 704 * 480 (SM124)
If you accept to loose one pixel at the left border, the
resolution in x-direction is 16 pixel more. 
1330.4looking better!.HEAVY::TAYLORSteve TaylorWed Nov 11 1992 12:3013
    Hi,
    	Thanks for the input!. I'm an absolute novis with the Atari!,
    therefore what do I need to do in terms of hardware and software
    changes?, and what do I need to aquire/buy?. I don't want to lay out
    loads of cash on a new monitor as this will impact my buying potential
    on software. My end goal is to hook it up to my MIDI instrument along 
    with some type of good quality sequencer like CLAB Notator or DR T. I
    guess I'll have to upgrade the memory as well!.
    
    	Best regards Steve.
    
    
    
1330.5CMOTEC::HARRISONWed Nov 25 1992 13:5316
I too am running an ST(E) off a VT240 monitor, and have the same problem of it
not going to the sides of the screen. I even took the monitor apart and fiddled
with the horizontal size pot, but still no luck.

As I see it there are two borders in question here (on the sides at least)

one that is usually white at the desktop, and outside of that the black one.

The White sides are where the ST scans to and the black is where the beam just 
doesnt reach. Even if you sort out using overscan this will only use up the
white border, and not touch the black, as the hardware is not scanning into it.

Anyone agree ?

Brynn Harrison.
1330.6re note 1330.5HEAVY::TAYLORSteve TaylorFri Nov 27 1992 16:1123
    
    
    
    
    Hi Bryn,
    
    I agree, I've been through the same loop. Ignoring the bit that
    doesn't get scanned !, this would still give you and extra 1/2 inch
    all round. I believe the overscan program must modify some pointers to
    make use of more memory for video scanning. I've tested a couple of games
    in the past which leave the whole screen accessable until you use the 
    desk top manager; then it goes back to its usual size!. 
    
    	Well from notes in this topic, it sounds like there is a solution
    to this and all we need is some knowledgable person to reply to this 
    note with the correct course of action for us novices to take!. Guess
    the best advice would be to buy a new monitor! - mind you, this would
    set you back a few quid for this type of resolution!.
    
    Please, more input from you Atari wiz kids !....
    
    /Steve.
    
1330.7Seen but not heard!!!FILTON::SMITH_TMon Jan 18 1993 14:4220
    Chaps
    	After reading your replies I was curious to see no one mentioned
    the lack of sound when using a VT24X monitor. I have assumed you are
    all discussing the VT241 colour monitor as was attatched to our VT240
    terminals and the old Rainbow PC.
    	Pins 1 and 5 supply the sound output to a monitor, so to achieve
    sound I have used one of the self contained and combined Speaker/Amp
    that would normally be used to get power sound from a Walkman.
    Basically the thing looks like a pair of stereo speakers that would
    plug into the earpeace connection and is powered from internal
    batteries. I tried an 8 ohm impedance speaker first which could not
    pick up the low power generated from the ST. Someone quoted a 30 Ohm 
    high impedance speaker was OK so I tried a 64 ohm and it was also
    barely audible.
    
    	Has any of you acheived sound in another manner ??
    
    Regards
    
    Tim S  
1330.8Another methodTIMMII::RDAVIESAn expert AmateurTue Jan 19 1993 13:218
    I use a VR241 monitor, and get sound from the stereo phono plugs
    patched to the DIN plug of an old radio/cassette player. Works fine for
    all the sounds you normally need to hear.
    
    For the WINNER.LZH demonstration (mentioned elsewhere) I did connect
    this into my Hi-Fi and got living stereo.
    
    Richard