Atari STe to LCD (via Scart) question

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wietze
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Atari STe to LCD (via Scart) question

Postby wietze » Wed Mar 27, 2013 7:05 pm

Good day,

I have a question with regards to hooking up the Atari STe to an LCD screen.

My intention is to connect my Atari STe to my LCD tv as follows:
- Atari 13 pin din to scart
- Using a scart to hdmi converter ( http://www.allekabels.nl/na/0/1063274/s ... ormer.html )
- Hdmi into the lcd tv

Firstly, I bought a 13 pin din to Scart cable, used a multimeter to measure it, and found out that the din-pin-to-scart-pin was not as listed on http://info-coach.fr/atari/hardware/interfaces.php. I tried it using the above setup, and did get no screen. I then resoldered the pins according to the pin layout in previous link.

This gave screen, however the screen flickers once in a while. This is not in a regular interval, but just randomly it seems. I recorded this flickering: http://frummel.org/~weedz/atari/flicker.mp4

I am wondering in which of the parts it went wrong. My soldering skills are quite low, so it may be that the cable is of poor quality. Measuring them with the multimeter at least gave me the the green light that all pins are connected properly.

So Im currently left with 2 questions:
- I failed to purchase a proper factory made 13 PIN DIN to Scart; can anyone recommend me vendor that sells this, so I can obtain myself a factory-grade cable
- Does anyone have a hunch why I got the flickering going on? Perhaps I should resolder one of the leads in the cable, or perhaps its not the cable at all but a common problem?

Any feedback is welcome.

Regards,
Wietze

P.s. I have been lurking a while on these forums, this is actually my first post; please be gentle ;)

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Re: Atari STe to LCD (via Scart) question

Postby Guest » Fri Mar 29, 2013 2:07 am

hi Wietze thanks for your post

its the same issues others with ste suffer

a bad component in the psu called a bridge rectifier

see this topic for more info viewtopic.php?f=15&t=24843

you should take the ste to someone like a tv engineer local if your not up for it

he/she will change the needed stuff

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Re: Atari STe to LCD (via Scart) question

Postby wietze » Fri Mar 29, 2013 7:56 am

Hi Simbo,

thank you for your comment. I have started to read on the post you linked and ended up finding the information at viewtopic.php?f=74&t=1681#p10147

Apart from the Atari STe, I hooked up an Atari MEGA 1 and an Atari STf. The last 2 gave me even more flickering when hooked up via Scart > HDMI (e.g. the STe gives by far the best quality HDMI output). All 3 Atari's work wonderfully when being hooked up to the SC1224 Color monitor; no flickering whatsoever.

I will read into the information about replacing the parts around the PSU this weekend, and see if I can find out the make/brand/type of PSU that I have in the Atari's, and make up a list of components I have to replace.

Regards,
Wietze

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Re: Atari STe to LCD (via Scart) question

Postby AtariZoll » Fri Mar 29, 2013 3:03 pm

LCD monitors usually have problems with Atari's video signal. Because it is not exactly regular TV/video standard. PSU fixing will not help in this case.
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Re: Atari STe to LCD (via Scart) question

Postby wietze » Sat Mar 30, 2013 8:52 am

Whenever I hook up the Atari directly to the scart from the TV, I do get image, without the flickering. However the display is (obviously) more blurry than through the scart to HDMI converter.

From what I deduce, the scart <> HDMI converter seems to have some trouble converting the signal to HDMI which makes the screen flicker (if that makes any sense?).

I wonder if I should test with different converters.

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Re: Atari STe to LCD (via Scart) question

Postby Fernecho » Sat Apr 06, 2013 1:20 pm

wietze wrote:
- Does anyone have a hunch why I got the flickering going on? Perhaps I should resolder one of the leads in the cable, or perhaps its not the cable at all but a common problem?



I think it's a common problem, I think that is not the fault of the cable.
I have two Atari, a 520 STFM , a 520 STe and a Samsung Sync Master 932MW TV .
The 520 STFM connected via the RGB ( DB-13 - Sacrt Cable ) not working properly, the screen moves and jump in all directions and it is impossible to read, however the 520 STe works perfectly with the same cable and monitor .
Another thing, I connected the 520 STFM via the RGB ( DB-13 - Sacrt Cable ) to a Samsumg LED TV and it works perfectly, so I think the problem is in LCD TV system that does not properly support the video signal of some ST.
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Re: Atari STe to LCD (via Scart) question

Postby Fernecho » Sat Apr 06, 2013 5:25 pm

wietze wrote:
So Im currently left with 2 questions:
- I failed to purchase a proper factory made 13 PIN DIN to Scart; can anyone recommend me vendor that sells this, so I can obtain myself a factory-grade cable
- Does anyone have a hunch why I got the flickering going on? Perhaps I should resolder one of the leads in the cable, or perhaps its not the cable at all but a common problem?



I do not know if it's a common problem, but I think the cable is not the problem.
I have two Atari, a 520 STFM, a 520 STe and a Samsung Sync Master TV 932MW.
The 520 STFM connected to the Samsung Sync Master TV 932MW LCD TV via RGB (DB-13 Cable - Sacrt) not working properly, the screen moves jumping in all directions and you can not see anything, but the 520 STe works perfectly with the same cable and LCD TV.
Another thing, I connected the 520 STFM to a Samsumg LED TV and it works perfectly, so I think the problem is in LCD TV system that does not properly support the video signal of some ST.
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Re: Atari STe to LCD (via Scart) question

Postby wietze » Sun Apr 07, 2013 9:15 am

If I connect the Atari's through the SCART <> HDMI converter box to the LCD, I get the flickering.

When I connect the scart immediately to the LCD, I get a steady screen, with some `shadowing' I believe its called; not all pixels are perfectly steady, and epecially small fonted text is hard to read. But at least the display is steady.

I will check soon with the s-video and composite video connections and post my findings.

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Re: Atari STe to LCD (via Scart) question

Postby NikiforosST » Fri Oct 25, 2013 6:58 pm

Hi here:) i have the same problem with my Atari STFM and HDMI 1080p upscaller! my STFM have damaged MC1377 chip and i can't take CVS signal or CSync for scart. So with some suggestions of my friend Anemos :D i found out that i must take H+V sync together with resistors (now i have 512 ohms to V and H sync wires) and connect them to scart pin 20,then connect pin 20 to pin 16 else no image at all, all the RGB wires are the same as other scarts. With this scart i have very good image on my TV TFT 32"wide no problem at all. http://i180.photobucket.com/albums/x207 ... C06807.jpg this is from my test with 170 οhms resistors but 510 are better for hdmi. And this is on my TV http://i180.photobucket.com/albums/x207 ... 210754.jpg i have changed the PSU with other from ebay btw. And now i bought this scart to HDMI 1080p upscaller http://www.ebay.ie/itm/271155770903?ssP ... 1497.l2649 i have remove the resistors from RGB signals (my scart had 68 ohms) and i have 512 οhms on H+V sync wires to pin 20+16. This video is BEFORE remove RGB registors and 170οhms registors ον Η+V sync. http://www.youtube.com/watch?v=brUge4aTi00 now i have only the image go in black and then back again, no moving image around anymore and its more stable. http://i180.photobucket.com/albums/x207 ... e589-1.jpg my monitor is LG LED 22" wide with DVI input, i have a cable HDMI to DVI. I want to make a small circuit like this http://www.mythtv.org/wiki/RGB_Scart to take Csync from H+V sync, but now i believe that it's not the problem...what are you suggesting? i must try it out?

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Re: Atari STe to LCD (via Scart) question

Postby catmando » Mon Oct 28, 2013 11:58 am

wietze wrote:If I connect the Atari's through the SCART <> HDMI converter box to the LCD, I get the flickering.

When I connect the scart immediately to the LCD, I get a steady screen, with some `shadowing' I believe its called; not all pixels are perfectly steady, and epecially small fonted text is hard to read. But at least the display is steady.

I will check soon with the s-video and composite video connections and post my findings.


I got the same flickering experience when I tried the exact same thing a year or two ago when I tried putting the scart through a hdmi upscaler. Never solved the problem so just sent the upscaler back to the shop.
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Re: Atari STe to LCD (via Scart) question

Postby NikiforosST » Tue Oct 29, 2013 4:39 am

Goodmorning! so i can't do anything? i thought that the synchronization faults! with some changes to my scart the picture is very better now, only some times picture becomes black and then come back again, but it is very stable. I will try a circuit to make H+V sync to Csync and i 'll see what happen next. I bought it from ebay so i can't take it back. Only 35 euros but i can use it to my satellite receiver is has scart (RGB) output.

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Re: Atari STe to LCD (via Scart) question

Postby Guest » Wed Oct 30, 2013 1:52 pm

i would measure the psu it uses while its on
and see if the voltage flickers also
this is frame dropout
perhaps its firmware needs a tweak

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Re: Atari STe to LCD (via Scart) question

Postby Guest » Wed Oct 30, 2013 2:37 pm

i dont see your problem with sync

the ste does have a version without the pal etc modulator
so negates to have the buffer stages

is this type the ste you have

you need to use different cables for st and ste

ste csync comes out on pin 12?? yes 12
to marry vsync to fast blanking on the scart isnt right
instead ground the fast blanking pin
its a bad idea for the ste
st perhaps

the fast blanking is a 'mode' of rgb transfer
and can be ignored by grounding its pin

this will switch mode with respect to the mode select pins state and sync inputs
ie if you use csync you may still also have to supply vsync or ground its pin on the scart
but not blanking you dont need it

if you dont need it ground it
if its an included mode pull it hi or supply it


different modes are 'detected' and state deduced from available inputs then decoded encoded
etc this is why i mention the units firmware

ive had similar issues and just had to write up a email report to the makers and they fixed it

your right its a common fault
if you leave a pin on scart open neither hi nor low it floats
and some pins are used mode float enabled

ill try find the stated standards page then you can see modern standards and any work around
more easily
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Re: Atari STe to LCD (via Scart) question

Postby Guest » Fri Nov 01, 2013 9:40 pm

replace the ste ~ carriers added 32mhz clock with mixed frequency pal etc :wink:

to a 32Mhz TTL clock crystal much like the usa machine :megaphone:
and watch for adding the cclk remove it and use 32mhz dead.... it will give a solid RGB
youll see the 32mhz clock input to the machine at the gst shifter pin 53 signal MC comes from the mono colour selectorr ic
use a 32,000,000 hz ttl clock
and try that
the drip drip uneven frame drip on the picture ive seen before in t'vs and vhs multi standard video sky boxes and ntl virgin etc cable etc
and it was caused by a similar issue
where interlaced is got from non interlaced its frame drip {drop out} because the maths is wrong perhaps in the adapter firmware
its dealing with 32MHZ/16 shifted 5 and 3 + other carriers
so strip off these rubbish and try that
its worth a try...!! and i have not tried it
you can use a switch to switch back to dot and main ste clock pin 3 U405 74S257 colour mono mode selector
but 32mhz is much better as its easier to compute
i bet the stupid GBsboards things will work fine
if uses strip off to a TTL only clock
you just need to then forget the modulator
even RGB is better if you use a standard
it would be nice if someone does an experiment

you can find a 32mhz ttl clock anywhere on old pcb
the shifter in the st machines input pin is similar osc 1 you should switch between 32mhz ttl or standard clock
the pal modulator in stfm has its own colour sub carrier crystal {same mc1377 ic}

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Re: Atari STe to LCD (via Scart) question

Postby Guest » Fri Nov 01, 2013 10:33 pm

to sum up

the ste and mega ste will add subcarriers to even the RGB output the st level runs the shifter clock 32.something mhz
so use a TTL 32mhz clock i think????

the converter will convert RGB to HDMI the more pure a RGB without added rubbish from the ste dot clock the better for conversion in maths
and get rid of the blanking as its added to the RGB path anyway on - Vsync
but i think most firmware will detect the accepts within the ataris RGB output due to the CCLK and inter modulation of the STE hsync
and will NOT like it pure RGB 32mhz is best as a test
so mod the clock and add a switch

i think its all thats needed and i dont have one

the blanking signal is not needed this way and the scart can negate using it as the gbs thing

and this encoder will like pure RGB with no accpets

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Re: Atari STe to LCD (via Scart) question

Postby NikiforosST » Mon Mar 10, 2014 7:39 am

sorry about my late replay on this topic. I have fixed the problem, i had wrong wires on my scart cable and i had problem with the signal. Now my ST works perfect on my LED 22" wide monitor with HDMI to DVI input. This is my last video with hdmi upscaller from scart http://www.youtube.com/watch?v=jOYqtap_ ... e=youtu.be , in the video i have and a KVM DVI switch to change between my desktop pc and Atari stfm, i have also a 15pin Dsub connection with analog port of the monitor to play high resolution of ST and a select swith for monochrome detect like photo here : http://i180.photobucket.com/albums/x207 ... etect1.jpg
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Re: Atari STe to LCD (via Scart) question

Postby Arkemath » Mon Mar 10, 2014 9:30 am

Hi,

NikiforosST, can you specify what you have done to the SCART cable ?

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Re: Atari STe to LCD (via Scart) question

Postby NikiforosST » Mon Mar 10, 2014 10:08 am

I don't remember now the combination with resistors and numbers, my friend Anemos help me to fix it, you can ask him if you want. But i remember that you must do some combinations with pin 16 and 20 on scart and H + V sync to play right on St pin and pin 8. But you need to add some registors between them. I must say that my STFM has broken MC1377 chip and i have removed the tv modulator, so signal CVS doesn't exist and pin 2 on my ST is dead, i can't take CVS signal, neither composite sync. Only RGB and monochrome signal is working.

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Re: Atari STe to LCD (via Scart) question

Postby wietze » Mon Mar 10, 2014 2:33 pm

Hi NikoforosSt, could you tell me which HDMI upscaler you have?

If that works perfectly for you, I am most interested in obtaining the exact same upscaler as well!

Please let us know which brand/type etc.

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Re: Atari STe to LCD (via Scart) question

Postby NikiforosST » Mon Mar 10, 2014 5:35 pm

hi again! the model is this: http://www.ebay.ie/itm/SCART-HDMI-to-HD ... 2ecccb6662 and http://www.ebay.ie/itm/gib-Lenkeng-LKV3 ... 27d963764c i believe all models can work too. I found the schematic with the scart cable from my friend Anemos, i check the registors now i have 1kohm in pin16 and 2 X 510 ohms in pin20, check the schematic below. We had tried many combinations ONLY these in the draw working. This scart doesn't work in my 32" TFT TV i see a black screen, it works only with scart to HDMI upscaller, i don't know why, but it doesn't matter.
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Re: Atari STe to LCD (via Scart) question

Postby TeaTimeMyDear » Thu Jun 05, 2014 8:14 am

Hello to all.

I'm an old geek who decided to reactivate an old 1985 Atari 520 STF and I bought a cheap brand LCD screen (about 90 euros) giving me as chalenge to run it with SCART RGB mode on my ST machine.

Of course as I read on forums, i was faced with the same usual problems with straight SCART plugging - whether in 50 Hertz or 60 Hertz functioning.

I then bought the same converter HDM than NikiforosST (about 50 euros - see above) but then I had very big problems of flicking (worse than those described in the above YouTube video) so I carefully followed the pattern established by his friend Anemos as described in NikiforosST‘s previous post to modify SCART plugging for specific HDMI emulation: now it works without any problem of flicking or degradation of image quality !!!...

Therefore I testify to the quality of NikiforosST’s pattern for an HDMI emulation : this is a really good idea to have thought of using modulation with PINS (H + V Sync) which is perfectly emulated with an HDMI converter.

Nota:

Unless I am mistaken, it lacks on this diagram connections for audio output on SCART PIN 2 and PIN 6 : of course I kept them on the SCART socket .

In addition and contrary to the diagram, I have kept the original 150 ohm resistors on the SCART RGB PINS (PINS 7, 11, 15) : maybe that’s why my image seems slightly "washed" but maybe I’m wrong and this is due to the low quality of my LCD.

For those who engage in this implementation, count on 2 or 3 hours of work if like me you are an amateur in electronics and not a superman of the soldering iron.

In addition, it is recalled that the gray DIN PIN 9 (Horizontal Sync) is not generally used in the original Atari ST SCART cables : you will have to think about disassembling the DIN 13 plug to possibly re-weld it before considering then weld it on the SCART plug.

Thank you to our two Awsome Greek Geeks for having spent time on this issue : that allows me today to enjoy high image quality (720p or 1080p) while I was unable to find a viable solution to display a single stable image on my LCD screen (I didn’t try VGA Box solution anyway..).

Best Regards.

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Re: Atari STe to LCD (via Scart) question

Postby NikiforosST » Thu Jul 17, 2014 7:51 am

Goodmorning from Greece! sorry i haven't seen your post. I am happy that you like this trick, i want to thank my friend Anemos, this was his idea, i mean the scart cable. I am very happy with it. We haven't the sound in the schematic because my STFM has modifications and i have two RCA outputs in the back for the sound, i have connected my STFM to a 4-channel sound mixer and Yamaha home cinema receiver. So i don't want sound to my scart cable, my LED 22" widescreen monitor haven't any speakers! this scart modification on my AOC 32" TV doesn't work! i don't know why but i don't care, i want to use only the monitor. Now for your notes : "I have kept the original 150 ohm resistors on the SCART RGB PINS (PINS 7, 11, 15)", you must remove these resistors, maybe you have no good colors, you need them only if your scart goes on a TV. Pin9 must be use here, else you have no image, i have try it, other scarts are for TV not for ΗDMI upscaller! pin13 are ground to the shiled so black pins on scart, if you put it on other pins we have problems with image stability. This schematic made from Anemos after many many different tries on my scart, i believe only exactly like the schematic works without any problems. If someone tries it else, he can write it here, but when something plays nice and good you don't have to touch it, else maybe you have problems...so i don't want to make any others tries with the modificated scart cable, it's perfect right now as it is.
You can also have monochrome image (640x400) to your monitor look here : http://i180.photobucket.com/albums/x207 ... ea1c1f.jpg
i have soldered a svga 15pin output at the back and rca outpunts and composite video signal, in this case you need a monochrome detection switch on-off, you can see it in the photos.
http://i180.photobucket.com/albums/x207 ... f5b6e3.jpg

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Re: Atari STe to LCD (via Scart) question

Postby TeaTimeMyDear » Thu Jul 17, 2014 10:22 am

Hi NikiforosST.

Thank you for your research on this issue.

Of course your established SCART pattern seems to be the best for this type of HDMI upscaller (i mean without an additive scandoubler wich would improve the sharpness) but has the value of the resistor connecting the two pins (H + V Sync) been obtained in a empirical way ?..so maybe it's optimized for this type of device and it would be nice to get feedback on other brands HDMI upscaler.

So: not so much aliasing, stable image, undistorted color - it's really good.

Yes I also tested this modified SCART straight cable on my cheap LCD TV set and also on VGA card GBS-8200 and indeed there is no picture displayed - we may believe this hooked SCART cable seems exclusively functional for HDMI Upscaler.

The only downside is that this cheap upscaler doesn't enable manual image scalling so that's relatively small even in 1080i ... unless connecting the set to a LCD TV set wich does it that's a little bit frustrating... but the HDMI upscaler solution seems the most stable for me - in fact my new VGA GBS-8200 card (less than 30 euros on Ebay) wich enables manual image scalling also brings all issues identified by users (ghost-like residue of the image, white dots etc...) and i'm afraid we can't really find stable solution also with GBS-8200 version 4.

Best regards from France - happy to read you.

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Re: Atari STe to LCD (via Scart) question

Postby NikiforosST » Thu Jul 17, 2014 2:13 pm

Look my atari stfm had damaged motherboard, i have done some wrong moves on my RF modulator and i broke it. then i haven't CVS video, composite sync and RF output. I think maybe the MC1377 chip burned. I didn't find it out a solution so with my friend Anemos we have some scart modification ideas. The stock Scarts for Atari ST's use pin 2 for composite sync signal, that's why on my Atari can't work. Now after many many years i have another mobo with working circuit because old one video failed, i have some vertical lines (black+white) i don't know why....i have tried everything!
So i can tell you only what scart worked for me on my TV, it's the same like before but you need to take H+V sync from ST to scart with 170ohms registors (NOT 510 ohms!!!) and you must connect pin 20 with pin 16 on scart cable, NOT the connection from atari pin 8. I have another scart with this modification for my tv, but on the hdmi upscaller has many many issues.

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Re: Atari STe to LCD (via Scart) question

Postby TeaTimeMyDear » Thu Jul 17, 2014 3:56 pm

Hi NikoforST.

Thank's for reply.

Ok i do understand why you had to find some tricks because of you burned MC1377 chipset.

Thank's for giving a way to hack original SCART cable to plug Atari ST staight on TV set combining (H+V Sync) signals - that's fun it's maybe THE solution i had no infos about and that's why i tried to find other ways to plug Atari on LCD TV via HDMI upscaler or VGA box.

For connecting ST straight on LCD TV set did i understand you really mean to mix (H+V Sync) via 2*170 Ohms resistors and then plugging result signal simultaneously on SCART pin 20 AND pin 16 ?.

"Now after many many years i have another mobo with working circuit because old one video failed, i have some vertical lines (black+white) i don't know why..." : do you mean you recently had bad issues with your Atari video working circuit ?... sorry for it - hope you will find a way to deal with this issue .

I would have a subsidiary question : yes indeed (H+V Sync) signals are often mixed with only 2 resistors - i read some say that's not 100% safe for ST video circuits and it's better to use a logical gate instead (e.g 74HC86 or 74HCT86) to re-modulate a clean CSync signal - is it true and do you think that's better for our HDMI upscaler ?.

Sincerely your - nice to read you.


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