Another failed ST -> vga experiment for me :)

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Re: Another failed ST -> vga experiement for me :)

Postby FedePede04 » Fri Jun 17, 2011 8:10 am

wongck wrote:
FedePede04 wrote: so i ended up buyning a lcd tv 14 days ago.
a Packard bell Maestro 220 TV.
for me the picture quality is ok (not perfect).


It is like a TV output.
Even back when I was using my STFM on a 19inch TV CRT, it has white shadow on the text & lines.


Hi Wongck.

I might have the advantage here, I have never seen how good Atari stood on a good monitor, when I had my Atari, I used a TV for a long time,
so I got a monitor from a friend but could only get a composite cable, so I have only seen a blur picture on the Atari. So for me it's an upgrade,
but if you was used to a good picture, then it would probably be the opposite.
but now I can wait until some finds a good and easy solution.

I upload a few other pictures taken with another camera and remove a few of the old ones.
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sometime my English is a little weird, Google translate is my best friend :)

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Re: Another failed ST -> vga experiement for me :)

Postby wongck » Fri Jun 17, 2011 11:43 am

I had used on a TV but moved to a CCTV using the composite output. It was black & white but not hi-rez.

As for LCD TV on an Atari, there were alot of discussion on this topic for few years back.
One such thread is here The TFT LCD Buying Advice Thread
You may want to do a search for more.

Now my Falcon & TT hooks up to my LCD monitor.
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Re: Another failed ST -> vga experiement for me :)

Postby FedePede04 » Fri Jun 17, 2011 12:36 pm

ok you had it even wors end me. :o

i have read the thread you posted, the problem was none of those LCD screens, are in sale any longer.
i also read a couple of threads about line doublers, and couldn't find any good result.
so i decide to buy a LCD TV.
i try 3 diffident TV a 22" Philips, if the screen was white massive screen corruption,
i also try a 24" Samsung Monitor with TV in the problem with, the Samsung was double text (shadows),
so this was the best that i try,
like i say its fare from prefect but it's ok for me,
and farther down the road i hope there will come something easy and better.:D

/peter
Btw.
thank for the link.
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Re: Another failed ST -> vga experiement for me :)

Postby Official Ninja » Fri Jun 17, 2011 1:37 pm

Problem I had with all the LCD monitors and TVs I have tried, they did not support both PAL and NTSC on the VGA port. Some did on the composite or RF, but not VGA or Component. Using RGB to VGA or RGB to YUV converters.

I did have excellent luck with good old VGA CRT monitors using the same converters. All the ones I have tried work fine with 50 or 60hz, some of them squeeze the 50hz picture a little but it is far from bad.

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Re: Another failed ST -> vga erxperiement for me :)

Postby tvcf » Thu Dec 01, 2011 12:11 pm

hello,

i have a gbx-8220 rev. 3. I have connected:

R -> R
G -> G
B -> B
vs & hs -> S
ground -> ground

the atari ste dont works. no signal.

Can you help me

thanks

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Re: Another failed ST -> vga experiement for me :)

Postby Shredder11 » Thu Dec 01, 2011 2:06 pm

Did you follow the info on page three of this topic? Anemos posted a wiring diagram pic:

http://www.atari-forum.com/viewtopic.php?f=15&t=17153&p=187640#p174778


I have successfully been using my Super Color HD video convertor box since 2009, but I am interested in buying a BGS-8220 to try out.

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Re: Another failed ST -> vga experiement for me :)

Postby tvcf » Thu Dec 01, 2011 3:09 pm

hello,

i have not connector, i try to use other input. (Anemos schema) page 2.
i use spin rgbs input

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Re: Another failed ST -> vga experiement for me :)

Postby spiny » Fri Feb 10, 2012 10:18 pm

hi guys, my board turned up the other day, a 'v4' and i've wired it up as per the pics earlier in the thread but can't get it working.

if i use the 510 resistors, i get nothing, just a 'no signal' from the box. if i take the resistors out, i hget this:

Image

however, when i take the cable out of the atari, very very briefly i see the desktop.

any pointers ?

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Re: Another failed ST -> vga experiement for me :)

Postby Shredder11 » Fri Feb 10, 2012 10:55 pm

My 8200 v4.0 2011-11-25 turned up the other day as well, so I just need to wire up a suitable cable.

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Re: Another failed ST -> vga experiement for me :)

Postby spiny » Sat Feb 11, 2012 12:27 am

just tried using composite (pin 2) and connecting that to 'S' on the 8200, still not working, though th monitor now shows as solid green, so it's different at least :)

i'll dig out my phono leads in the morning and have a go at the Y Pr etc sockets, it's late here and i've just leant on my soldering iron while reaching for my beer ...

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Re: Another failed ST -> vga experiement for me :)

Postby nativ » Sat Feb 11, 2012 12:51 am

:oops: ouch! when that happens it's time for sleep!! I hear Lavender is good for burns...
Atari STFM 512 / STe 4MB / Mega ST+DSP / Falcon 4MB 16Mhz 68882 - DVD/CDRW/ZIP/DAT - FDI / Jaguar / Lynx 1&2 / 7800 / 2600 / XE 130+SD Card // Sega Dreamcast / Mega2+CD2 // Apple G4

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Re: Another failed ST -> vga experiement for me :)

Postby spiny » Sat Feb 11, 2012 2:00 am

nativ wrote::oops: ouch! when that happens it's time for sleep!! I hear Lavender is good for burns...



more beer seems to be helping too :)

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Re: Another failed ST -> vga experiement for me :)

Postby jokker » Sat Feb 11, 2012 2:17 am

I did R, G, & B to each other and then tied Hsync and Vsync on the Atari together to the sync to the Sync (S) on the GBS board as well as GND to each other.

Nothing else and it worked fine for me. I also had to set the resolution to 800x600 on the GBS board.

Some pictures here of my setup...
http://atari-forum.com/viewtopic.php?f=15&t=22490#p199721

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Re: Another failed ST -> vga experiement for me :)

Postby spiny » Sat Feb 11, 2012 2:30 am

jokker wrote:I did R, G, & B to each other and then tied Hsync and Vsync on the Atari together to the sync to the Sync (S) on the GBS board as well as GND to each other.

Nothing else and it worked fine for me. I also had to set the resolution to 800x600 on the GBS board.

Some pictures here of my setup...
http://atari-forum.com/viewtopic.php?f=15&t=22490#p199721


interesting, thats exactly what i've done.

i'm using an STFM , what did you use ?

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Re: Another failed ST -> vga experiement for me :)

Postby jokker » Sat Feb 11, 2012 2:52 am

I did that on a MegaSTE, but I have not tried anything else with it...

Perhaps I should pull out an STFM and see if I can get it to work there.

*update*
I tried it on an STFM that I had and indeed it didn't work properly. Pulling the HSync caused it to appear briefly but then it looses sync as expected. I also found my screen to be a solid red unless I pulled red out and it became black.

So perhaps the STFM works differently enough for it to not work? I guess I should try a few more models over the weekend and see if I can get anything else to happen.

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Re: Another failed ST -> vga experiement for me :)

Postby Silly_Pony » Sat Feb 11, 2012 5:55 am

I use an STE:

No resistors, just RGB to the poles. H and V sync together to the SYNC pole. No resistors or caps.

Picture is found but gets lost again. hit the AUTO button and the board tunes in. Only needs to be done once, board remembers settings.

Image is perfectly stable now, just use trim pots to turn down the saturation.

After 5min of running, the picture becomes jittery and sometimes loses sync for a second. Leave for 5 more and it becomes stable permanently! You can leave it on for as long as you like now with no problem.

GBS-8220 V3.0 board is fitted inside my custom STE case, taking power from +5v rail of the STE PSU.
1040STe, 1040STf

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Re: Another failed ST -> vga experiement for me :)

Postby 1024MAK » Sat Feb 11, 2012 10:19 am

I don't recommend connecting Vsync and Hsync together on the Atari side :twisted:
These signals are used internally and looking at the 1040STF(M) schematic do not have any resistors to provide protection or limit the current :( .
If you connect them together, the respective outputs from the Atari custom chip will fight one another...
On the STE, 33 Ohm resistors are fitted, so that may explain why it kinda works.
I have just got a GBS-8200 V4.0 board, and I will try mine. I also have an oscilloscope and various electronic parts so can do some tests.
I can test on a STFM and a STE.
If you do want to try to combine the Vsync and Hsync together to make a composite sync, use 75 Ohm or 100 Ohm resisters between the Atari and the video board:-

Code: Select all

               ____
Hsync in -----[____]--------+
               ____         +---------------Csync out
Vsync in -----[____]--------+

Also on my GBS-8200 V4.0 board, Hsync (HS) and Sync (Csync) are connected together via a track on the PCB.
All the RGB input connectors all connect their respective input signals to the same inputs, so you can use either P3, P10 or P11. It makes no difference :mrgreen:

Mark
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Re: Another failed ST -> vga experiement for me :)

Postby spiny » Sat Feb 11, 2012 12:29 pm

cheers, just to be clear, you're saying to use pin 2 of the atari, and split it to the v andd h sync on the 8200 (with inline resistors) ?

thanks :)

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Re: Another failed ST -> vga experiement for me :)

Postby spiny » Sat Feb 11, 2012 2:33 pm

success !

just started trying differnt combinations of things and went back to trying the h and V from pins 9 and 12 on ST and it is now working with this setup:

R G B > R G B on 8200

H and V sync > 'S' on 8200 with a 47 resistor on the H and V lines

GND to GND

so:

Code: Select all

st - - - - - 8200
6  - - - - - G
7  - - - - - R
9  - 47R   - S
10 - - - - - B
12 - 47R  - S
13 - - - - - GND

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Re: Another failed ST -> vga experiement for me :)

Postby spiny » Sat Feb 11, 2012 2:39 pm

and some pics :)

med res, not perfect, but much better than my 'super HD converter' box - this is my STFM
Image

wiring - to be tidied :)
Image

working on Mega (no modulator) too
Image

Mega again:
Image

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Re: Another failed ST -> vga experiement for me :)

Postby 1024MAK » Sat Feb 11, 2012 5:47 pm

I've now got a working set-up as well.
To keep the stress on the Atari low, I opted to use a 74LS86 chip to mix the Hsync and Vsync to produce a nice clean composite sync.
I will publish the schematic as soon as I have drawn it!
Some pictures will follow in a mo...

Edit: Here are some pictures...
STE Low Res.jpg

STE Med Res.jpg

Work in progress.jpg


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Re: Another failed ST -> vga experiement for me :)

Postby 1024MAK » Sat Feb 11, 2012 8:12 pm

Okay, here is the schematic for the circuit that I used with the GBS-8200 V4.0 board.

74LS86 sync circuit V0,5.gif


I designed it to be a general purpose sync corrector and mixer circuit.
The chip (IC1) is a 74LS86. A 74HC86 and a 74HCT86 should also work (but have not been tested, yet).
All resistors are 250mW 5%. C1 is a 100nF capacitor, the type and voltage rating are not critical, but I suggest a ceramic type.
The items shown / marked JP1, JP2 and JP3 are two pin headers with jumper shunts.
For this application, you do not need to fit R1, R2, R7, R8 and JP3.
JP1 and JP2 need jumper shunts fitting. Or you can use wire links in place of them.

I used the P9 power connector on the GBS-8200 V4.0 board to "steal" a +5V supply for this circuit. Red is +5V, black is 0V/GND.
Connect the Atari STF(M)/STE up as per the table below.
On the schematic diagram, the output is called "Comp Sync out" but in the table I refer to the same signal as CSync.

Code: Select all

   Atari      signal      wire colour   GBS-8200 V4.0 board
13 pin DIN                                 P11 connector
    6 ------green video---green wire------------"G"
    7 ------red video-----red wire--------------"R"
    9 ------HSync---------to 78LS86 circuit
   10 ------blue video----blue wire-------------"B"
   12 ------VSync---------to 78LS86 circuit
   13 ------Ground--------black wire------------"GND"
            CSync from----grey wire-------------"S"
            78LS86 circuit
            No connection-yellow wire-----------"VS"


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Re: Another failed ST -> vga experiement for me :)

Postby Silly_Pony » Sat Feb 11, 2012 8:54 pm

In layman's terms, what's the advantage to using that circuit vs not using it?

I probably will built it but if you could convince me to do it sooner rather than later... :)
1040STe, 1040STf

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Re: Another failed ST -> vga experiement for me :)

Postby nativ » Sat Feb 11, 2012 11:40 pm

Looks a lot better than the Scart output I currently get on the ST!
Atari STFM 512 / STe 4MB / Mega ST+DSP / Falcon 4MB 16Mhz 68882 - DVD/CDRW/ZIP/DAT - FDI / Jaguar / Lynx 1&2 / 7800 / 2600 / XE 130+SD Card // Sega Dreamcast / Mega2+CD2 // Apple G4

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Re: Another failed ST -> vga experiement for me :)

Postby 1024MAK » Sat Feb 11, 2012 11:50 pm

I put together that circuit (using all four gates in the 74LS86 chip) to experiment with :mrgreen:
Now that I know it works (on my STFM and STE), It will be possible to simplify it somewhat :D

The advantages of using a logic chip are:
  • It will not excessively load the outputs from the custom Atari Glue chip.
  • It amplifies and cleanly mixes the horizontal and vertical sync signals to produce a clean signal for the GBS-8200 video converter.
  • It is more likely to work reliably (famous last words :wink: ) with all models / versions of the ST range of computers, and it may well work with other computers that also produce horizontal and vertical sync signals.
I do like very simple circuits (and well done to spiny getting the two resistor method to work :D ), but the simple resistor circuit may damage the output driver in the Atari Glue chip. Time for a quick bit of maths and a thought experiment:-
Now some of the time one of the sync signals will be high (+5V) and the other will be low (0V), with the two signals being connected together you have a total of 5V across the two resistors.

When using an STF(M), if these resistors each have a value of 47 Ohms, the total resistance is 94 Ohms. Current = voltage / resistance. So 5V divided by 94 Ohms = 53.2mA 8O :evil: Now that is likely to be more than the designers at Atari intended. Maybe more than double what was allowed for :twisted:
Now earlier in the thread I did suggest using 75 Ohm or 100 Ohm resisters. Even when using these values (if they work) results in a theoretical current of 33mA or 25mA :(
Now I don't know what the specification is for the output section in the custom Atari Glue chip. But then I don't expect anyone else does except for some former Atari staff.

For the sake of less than £5 worth of parts, I would rather not risk it.
I now know that 74LS86 chips work. Looking at the Hsync and Vsync signals on my oscilloscope, I think that either a 74HCT86 or a 74HC86 is very likely to work. I have a 74HC86 and may try it tomorrow.

On eBay 74LS86 chips are 5 for £1.00 (plus £2.50 P&P), see http://www.ebay.co.uk/itm/220659545904
I bought chips from posttrade before and like their service.
There are a number of sellers of 74HC86 chips, at the moment the lowest price is £2.02 for one with free P&P.

Mark
Falcon, Atari 520STFM, Atari 1040STE, more PC's than I care to count and an assortment of 8 bit micros (nearly forgot the Psion's)


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