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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Fri Jun 17, 2011 7:10 pm 



Joined: 20 Sep 2008
Posts: 41
Location: UK
Good point, I should have said. I tried PAL and NTSC games on the psone (it's chipped) and I get no input on my 8220.

I put a 50hz Sega Master System on the 8220, and it converted it to 60hz and displayed that fine.

dosucol1 got it working, but I haven't haven't been able to get hold of him for a while, hope the fella is okay, vanished off of all the messageboards that we're both members of.
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Fri Jun 17, 2011 7:40 pm 


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Quote:
I tried PAL and NTSC games on the psone (it's chipped) and I get no input on my 8220.

You could try using s-video lumiance instead of composite video for the RGB sync signal (PSOne multi AV output Pin 5 instead of 6) - might make a difference without the need to buy a sync stripper.


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Fri Jun 17, 2011 7:53 pm 



Joined: 19 Mar 2010
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You can even get a csync signal out of the psone, by modding the v & h sync and splicing them together. May sort your issue.
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sat Jun 18, 2011 12:03 pm 


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Awesome! 8)

You let us know when they are ready to order :wink: :)

-This wil also work for the Super Famicom and Megadrive?

-You also gona make a case just like the one for the slg-3000?

thanks.


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sat Jun 18, 2011 12:04 pm 



Joined: 20 Sep 2008
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Location: UK
Thanks for the replies. I'll have to try with a different RGB cable to see about swapping 5 for 6 (I have an official one at the moment which I don't want to butcher up)

fagin - Can you elaborate a bit more? Sorry, sometimes I can pick things up straight away, and other times the simplest thing baffles me completely!!

Ta
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sat Jun 18, 2011 3:21 pm 



Joined: 20 Sep 2008
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Location: UK
Just picked up a third party lead to play with, although i guess i could have messed around inside the console.

also found this http://www.retroleum.co.uk/electronics- ... -lcd-info/ which mentions pins 5 and 6 etc.

ta
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sat Jun 18, 2011 11:50 pm 



Joined: 07 Jun 2011
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Location: UK Geordie land
Hi pete.better late than never .
But yeah ,i should do a video of my pal-i psone working perfectly fine with this scaler.

The main problem it seems ,is just with the scaler and it's V settings.For my jp pre tmss mega drive the default settings at either of the 4 resolutions ,all work from the get go,but when i plug in my old style black ps2 ,the image is fine on the console's main bios/settings screen ,but using silent hill 3/gradius V as a test,this shows problems as soon as it starts displaying any content from disc (logos ,text ,loading screen).

Half the screen is missing off the bottom,sometimes the images ,text etc ,will just remain static and switching through the scaler's input sources and back to rgbs is the only way to refresh the screen ,but again,this will remain completely static and shaking.To correct it ,all i had to do was to first adjust the scaler's V size (making the V size smaller)and as soon as i started reducing its size ,the image became normal .Then just mess with the V position.

Now,if i go back to the main ps2 bios/settings screen,it will be completely borked ,but i just leave it like that ,as long as i know the game i run will be correct. Now my psone and ps1 , they run fine(but after correcting the ps2's problems ,this makes the psone completely borked,so i just have to re adjust the scaler's V size to fix the problem of the " no signal"/static image/half missing screen ) ,the scart cable is use for all the PSs ,the scart plug has the 220 uF caps on each RGB line.But when i made a sync splitter/cleaner RGB scart box for duddy roar and his commodore monitor,his md wouldn't work with it,but his AES and snes would.All i did to get his md to sync ,was build him a scart lead without the caps .

I'm positive the 1 scart lead i use for all the PAL-I sony consoles ,is a uk model.It has 2 Vss/gnd wires coming from the console's connector and these are not common to the 4 Vss/gnd pins in the scart plug(each go to 1 group/point of 2 Vss/gnd pins).It has the resistor across scart pins 8 and 16, I'm using rgbs @480p on the scaler,the clamp settings are at default.My lm18 is inside a scart switcher and it's powered by each console's Vcc scart pin(8),i've used a .1uF smoothing/decoupling cap across the lm18's power rails (right on top of the IC)as without it,i had niggles with a commodore 1080sd-1 monitor)) .And the lm18 is only supplying csync to the scaler's S (sync )point.Whether i use just one Vss/gnd pin on the scaler,or all of them ,it doesn't matter ,as all the Vss/gnd points on each of the scaler's input connectors are all common,same as the CSYNC and HSYNC(these two are connected to each other) and VSYNC points.

My scaler's psu is rated at 5Vcc @2.5 amps and never goes beyond or below the rated voltage stated.That diy slg is also powered from the output vga port of the scaler .But the only problem i do have now with that scaler,is a slight ghosting effect when using rgbs mode.Component is dot on though. Using a Sony KDL22PX300 playstation tv

Another game of note,regarding testing a scaler's ability to handle shadows (30hz flicker etc)is strider,on the mega drive ,a jp 60hz game.On the very first stage,there are these search lights/beams ,which go left and right ,this scaler just can't handle them .So now i have the scaler bug ,(and now i can finally get rid of my 1084sd-1 and 4/3 trinitron )what other reasonably priced scalers would be able to handle those types of common problems ?
Available in the UK/euro


Last edited by dosucol1 on Sun Jun 19, 2011 12:55 am, edited 3 times in total.

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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sun Jun 19, 2011 12:09 am 



Joined: 20 Sep 2008
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Location: UK
Glad to hear you're still around :-) I'll have a proper read of that in the morning, and then probably pull apart some cables!!

Cheers :-)
Fagin has some scaler comparison vids on YouTube doesn't he?

Pete
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sun Jun 19, 2011 12:14 am 



Joined: 07 Jun 2011
Posts: 32
Location: UK Geordie land
Aye,but i don't think any cover the scaler's handling of games with different rates of shadow hz flicker .


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sun Jun 19, 2011 12:51 am 



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http://retrogaming.hazard-city.de/


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sun Jun 19, 2011 5:46 pm 



Joined: 20 Sep 2008
Posts: 41
Location: UK
Well I'm at a complete loss then lol. Checked my cable and it's definitely getting Sync from the right place. Removed the capacitors from the cable and still no image.

I'll have to wait for a sync strike I reckon!

Pete
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Last edited by hellbelly on Sun Jun 19, 2011 8:50 pm, edited 1 time in total.

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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Sun Jun 19, 2011 7:28 pm 


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Hey Pete, I`m just putting together the test units for Fagin and ZOM. Perhaps you want one for your setup? I`m curious if sync strikes works here. :) Leave me your adress via PM
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 8:33 am 



Joined: 19 Mar 2010
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Hellbelly,
Read here http://www.gamesx.com/wiki/doku.php?id= ... ion_1_sync

Whilst I don't have a PSONE I will be testing Bencao's Sync Strike (and SLG3000) with RGB SCART enabled:

PCE
SNES
Saturn
PS2
NEOGEO AES
NEOGEO CD
Dreamcast
XBOX
XBOX360

Based on my testing with my own sync splitter, I would suspect the only problem console will be the PCE. The RGB circuit is unknown and I may need to "tinker" with it to get this working with the Sync Strike. It does not even work with my own sync splitter, but I have not really opened it up to see if I can resolve the issue yet..... this will undoubtedly come. I can't see this being unsumountable.

Dosucol1,
What you state of the CGA2VGA scalers "issue" is indeed correct, with regard to the 30khz drop shadows. However (and Fudoh will rip me a new arse for saying this lol) you can drastically reduce this "issue" imo by using the SLG3000 as well. OK... it's not perfect but it makes the issue less of an issue to the "untrained" eye. Since your eye is getting "trained" I'd suggest you need to look elsewhere though.

As you have noted, Fudoh's site will give you the "one stop shop" to information required for looking at another scaler solution to get this mentioned issue corrected.

If you only want component input, then the HDBOX Pro (or one of it's clones) will be one of the cheapest ways of sorting this. However this does not allow RGBs input. I may buy one in the future to see if I can butcher it to take a RGBs input, as I have no idea what onboard video circuitry it has. I don't hold out much hope though.

Based on the information from Fudoh and what I have bought myself, I would recommend a Cinemateq Picture Optimiser. They provide a great picture (leaves the CGA2VGA for dead) and can be picked up for as little as £50 from eBay..... if you're lucky. The bonus of this scaler is that it will natively accept a RGBs (RGB SCART) input with no other device needed. The Picture Optimiser Plus is the better one to get as it will work out of the box with the SLG3000. The Picture Optimiser will need a sync polarity changer circuit to work correctly with the SLG. However these scalers don't accept a 480p input. Nothings that straight forward. lol

The more and more you get in to this, the more and more you will realise that a "choice" of devices is the reality...... rather than a single device.

All in my opinion.
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 12:48 pm 



Joined: 07 Aug 2006
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Location: Sydney, Australia
bencao74 wrote:
Image

highres
http://4.bp.blogspot.com/-nWWfOmewlTs/TfnbJPdM1fI/AAAAAAAACrw/yxDcTGJwYW0/s1600/REAL_HSYNC.JPG

I`ve put it into NAND gates. I was hoping the schematic is correct ;)? Do you see any flaws?


That doesn't really make horizontal sync, pre/post equilisation pulses and a bit of the vertical sync pulse are still present in the output. Have a look at the vertical blanking area on a CRO and see for yourself.


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 2:36 pm 



Joined: 07 Jun 2011
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Location: UK Geordie land
hellbelly wrote:
Well I'm at a complete loss then lol. Checked my cable and it's definitely getting Sync from the right place. Removed the capacitors from the cable and still no image.

I'll have to wait for a sync strike I reckon!

Pete

Right then,i WILL do a short youtube video (minus the DIY slg)just to show my psone working with that scaler.


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 2:55 pm 


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fagin wrote:
If you only want component input, then the HDBOX Pro (or one of it's clones) will be one of the cheapest ways of sorting this. However this does not allow RGBs input. I may buy one in the future to see if I can butcher it to take a RGBs input, as I have no idea what onboard video circuitry it has. I don't hold out much hope though.

HDBP also uses the TrueView 5725 and the layout is similar to the CGA to VGA, it's just that there aren't any "convenient" RGBs inputs on the board outside of the 5725's direct pins.
The other thing is that TVia didn't offer any datasheets for online distribution, but you could always find out which pins to use by comparing it with the CGA to VGA. (the CGA to VGA is actually a direct clone of TVia's suggested "Arcade Game Converter", btw)

If the HDBP's firmware supports any other input than YPbPr, that I do not know.
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 2:58 pm 



Joined: 20 Sep 2008
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Location: UK
No need to go that far :-) perhaps my scaler has a different firmware on it or something. When I get home late I need to check the link by fagin and see I'd that clears it up (cheers fagin)

My modded PCE works great with the scaler, I used just 3 transistors to amplify the RGB signals, can't remember if tapped sync or video from the exp bus when I modded it though. It goes crazy on my old samsung TVif directly plugged in, but the scaler handles it fine.

I tried my MD on it, the sync is all over the place. But when I plug the SMS converter into the MD the picture is perfect?! Very odd. That's using comp video or comp sync from the MD.

Ta
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 7:13 pm 



Joined: 07 Jun 2011
Posts: 32
Location: UK Geordie land
fagin wrote:
Hellbelly,
Read here http://www.gamesx.com/wiki/doku.php?id= ... ion_1_sync

Whilst I don't have a PSONE I will be testing Bencao's Sync Strike (and SLG3000) with RGB SCART enabled:

PCE
SNES
Saturn
PS2
NEOGEO AES
NEOGEO CD
Dreamcast
XBOX
XBOX360

Based on my testing with my own sync splitter, I would suspect the only problem console will be the PCE. The RGB circuit is unknown and I may need to "tinker" with it to get this working with the Sync Strike. It does not even work with my own sync splitter, but I have not really opened it up to see if I can resolve the issue yet..... this will undoubtedly come. I can't see this being unsumountable.

Dosucol1,
What you state of the CGA2VGA scalers "issue" is indeed correct, with regard to the 30khz drop shadows. However (and Fudoh will rip me a new arse for saying this lol) you can drastically reduce this "issue" imo by using the SLG3000 as well. OK... it's not perfect but it makes the issue less of an issue to the "untrained" eye. Since your eye is getting "trained" I'd suggest you need to look elsewhere though.

As you have noted, Fudoh's site will give you the "one stop shop" to information required for looking at another scaler solution to get this mentioned issue corrected.

If you only want component input, then the HDBOX Pro (or one of it's clones) will be one of the cheapest ways of sorting this. However this does not allow RGBs input. I may buy one in the future to see if I can butcher it to take a RGBs input, as I have no idea what onboard video circuitry it has. I don't hold out much hope though.

Based on the information from Fudoh and what I have bought myself, I would recommend a Cinemateq Picture Optimiser. They provide a great picture (leaves the CGA2VGA for dead) and can be picked up for as little as £50 from eBay..... if you're lucky. The bonus of this scaler is that it will natively accept a RGBs (RGB SCART) input with no other device needed. The Picture Optimiser Plus is the better one to get as it will work out of the box with the SLG3000. The Picture Optimiser will need a sync polarity changer circuit to work correctly with the SLG. However these scalers don't accept a 480p input. Nothings that straight forward. lol

The more and more you get in to this, the more and more you will realise that a "choice" of devices is the reality...... rather than a single device.

All in my opinion.


i'll keep a look out for a cpo and chase up your original cpo thread ,r.e the hex inverter IC's you used for changing the polarity .I have a few hcf4001 NOR gate ICs,so i could probably use them as a NOT gate .


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 8:51 pm 



Joined: 07 Jun 2011
Posts: 32
Location: UK Geordie land
My PAL-I psone working with the GBS8220
http://www.youtube.com/watch?v=PksiwNd9cyg

The bug i mention mention which happens with the GBS ,and refer to the same bug also with the hdbox pro,it's actually the DVDO iscan pro whch has the same bug,not the hd box pro.

Quote:
http://retrogaming.hazard-city.de/

Image
the iScan Pro has a 240p detection where no deinterlacing is applied, but it has a bug where weird pixels appear where none are supposed to be (see picture below). It's not a problem of the machine per se, it's a problem of the used SIL503 chip. It sounds more extreme though than it actually is.


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 9:08 pm 



Joined: 07 Jun 2011
Posts: 32
Location: UK Geordie land
viletim wrote:
bencao74 wrote:
Image

highres
http://4.bp.blogspot.com/-nWWfOmewlTs/TfnbJPdM1fI/AAAAAAAACrw/yxDcTGJwYW0/s1600/REAL_HSYNC.JPG

I`ve put it into NAND gates. I was hoping the schematic is correct ;)? Do you see any flaws?


That doesn't really make horizontal sync, pre/post equilisation pulses and a bit of the vertical sync pulse are still present in the output. Have a look at the vertical blanking area on a CRO and see for yourself.


Off topic here ,but a question i still need answering is, how does the SLG3000 adjust the black levels (thickness) of the scanlines ?Is it creating some kind of scanline filter ,thus every odd or even line can be given more or less of an impact using the pots?


Last edited by dosucol1 on Mon Jun 20, 2011 10:53 pm, edited 1 time in total.

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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Mon Jun 20, 2011 9:56 pm 



Joined: 19 Mar 2010
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dosucol1 wrote:
viletim wrote:
bencao74 wrote:
Image

highres
http://4.bp.blogspot.com/-nWWfOmewlTs/TfnbJPdM1fI/AAAAAAAACrw/yxDcTGJwYW0/s1600/REAL_HSYNC.JPG

I`ve put it into NAND gates. I was hoping the schematic is correct ;)? Do you see any flaws?


That doesn't really make horizontal sync, pre/post equilisation pulses and a bit of the vertical sync pulse are still present in the output. Have a look at the vertical blanking area on a CRO and see for yourself.


Off topic here ,but a question i still need answering is, how does the SLG3000 adjust the black levels (thickness) of the scanlines ?


I doubt you will get that openly discussed on this forum by Bencao - not that I blame him. That isn't the only thing that sets the SLG above that of the "other" device schematics freely available.
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 12:09 am 


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The way the SLG3000 works was openly discussed when the unit was created, so at least the basic function isn't some kind of secret I guess. The SLG3000 does not adjust the thickness of the scanlines at all. All it does is darken every second line by putting a resistor in line to the actual signal (one resistor for every color channel, R/G/B). Using the adjustable resistors you can adjust the scanline denstity (up to 100% which means complete black).


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 7:02 am 



Joined: 20 Jun 2011
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Bencao hello, is what you will put your scart to vga for sale soon? and at what price? I am very interested, let me know thank you and it's great work!


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 8:54 am 


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Fudoh wrote:
The way the SLG3000 works was openly discussed when the unit was created, so at least the basic function isn't some kind of secret I guess. The SLG3000 does not adjust the thickness of the scanlines at all. All it does is darken every second line by putting a resistor in line to the actual signal (one resistor for every color channel, R/G/B). Using the adjustable resistors you can adjust the scanline denstity (up to 100% which means complete black).


Exactly, that`s how it works... the schematic is no secret I guess. Much work was going into the PCB Design, Production, selection of parts, case design, WEEE (electronic waste), PCB Assembly and so on.

Winni tried different schematics and approaches like replacing the adjustable resistor with DIP switches and fixed resistors. On the first version it wasn't clear either if we need a sort external PSU. Much time was spended here to get a good and stable power supply. At the end we disscussed the connector question here in the forum :)

Anyway, bit of project history.

Thickness of scanlines: Of course it is possible to choose a higher resolution than 480p. Then you get thinner and more scanlines....
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 9:12 am 


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thanks a lot for all the kind and very motivating PMs in the last time for the sync strike project :))

Project status is that the minimal goal is achivied:

RGB Scart -> Sync Strike -> GBS something Scaler -> SLG3000 -> LCD with scanlines

per Plug and Play

I`ve finished assembling 3 test units and now I`m going to order some parts for the first batch.

It would be fine for me to check the interest on SYNC Strike, so the pre-order is opened.

Just mail me (http://www.arcadeforge.de/?page_id=838) or send me a PM with

- Email
- Nick (if you have one)
- how many
- adress

I put you on my pre-order list for Sync Strike (first come first serve).

Price information will be posted as soon as possible. I`ve to search for some cheaper components. Bad example: the switch for selecting between hsync and csync costs currently 2.20€ ;) that is not necessary. Ordering more parts will result again in a cheaper price.
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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 2:32 pm 



Joined: 20 Sep 2008
Posts: 41
Location: UK
dosucol1 wrote:
My PAL-I psone working with the GBS8220
http://www.youtube.com/watch?v=PksiwNd9cyg


Thanks for taking the time to make and share the video, wish mine did that lol! I've just had the chance to try the 1 VGA output GBS board, still no luck with the psone on that, but the DC doesn't work either, works fine on my 2 VGA output GBS board though with the same lm1881 etc. I guess you get these quirks with different versions, different firmwares etc.

Fagin - the link on gamesx wiki looks hopeful. I'm going to resist tinkering with my last remaining PSone until after I've tried a Sync Strike. Shame, as a few weeks ago I had about 5 of the blighters knocking around but wanted shot of them, and then I discover the GBS boards ;)

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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 3:16 pm 



Joined: 07 Jun 2011
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Location: UK Geordie land
bencao74 wrote:
Fudoh wrote:
The way the SLG3000 works was openly discussed when the unit was created, so at least the basic function isn't some kind of secret I guess. The SLG3000 does not adjust the thickness of the scanlines at all. All it does is darken every second line by putting a resistor in line to the actual signal (one resistor for every color channel, R/G/B). Using the adjustable resistors you can adjust the scanline denstity (up to 100% which means complete black).


Exactly, that`s how it works... the schematic is no secret I guess. Much work was going into the PCB Design, Production, selection of parts, case design, WEEE (electronic waste), PCB Assembly and so on.

Winni tried different schematics and approaches like replacing the adjustable resistor with DIP switches and fixed resistors. On the first version it wasn't clear either if we need a sort external PSU. Much time was spended here to get a good and stable power supply. At the end we disscussed the connector question here in the forum :)

Anyway, bit of project history.

Thickness of scanlines: Of course it is possible to choose a higher resolution than 480p. Then you get thinner and more scanlines....


Fudoh wrote:
The way the SLG3000 works was openly discussed when the unit was created, so at least the basic function isn't some kind of secret I guess. The SLG3000 does not adjust the thickness of the scanlines at all. All it does is darken every second line by putting a resistor in line to the actual signal (one resistor for every color channel, R/G/B). Using the adjustable resistors you can adjust the scanline denstity (up to 100% which means complete black).


Thank you both!
Something which left most of us scratching our heads ,thinking, of what trickery was at work inside the SLG3000 ,turns out to be oh so simple .It's that saying, "the best inventions are the simplest " 8)

Paid for my SLG3000 at 12.54 am today


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 3:25 pm 



Joined: 07 Jun 2011
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bencao74 wrote:
thanks a lot for all the kind and very motivating PMs in the last time for the sync strike project :))

Project status is that the minimal goal is achivied:

RGB Scart -> Sync Strike -> GBS something Scaler -> SLG3000 -> LCD with scanlines

per Plug and Play

I`ve finished assembling 3 test units and now I`m going to order some parts for the first batch.

It would be fine for me to check the interest on SYNC Strike, so the pre-order is opened.

Just mail me (http://www.arcadeforge.de/?page_id=838) or send me a PM with

- Email
- Nick (if you have one)
- how many
- adress

I put you on my pre-order list for Sync Strike (first come first serve).

Price information will be posted as soon as possible. I`ve to search for some cheaper components. Bad example: the switch for selecting between hsync and csync costs currently 2.20€ ;) that is not necessary. Ordering more parts will result again in a cheaper price.


I guess later (after it's completely tested /refined etc and on sale to the public)maybe we'll see a case of some sorts,like with the SLG3000 ?


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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 3:42 pm 



Joined: 07 Jun 2011
Posts: 32
Location: UK Geordie land
bencao74 wrote:
Fudoh wrote:
Otherwise very nice design, very compact - nice!

fagin wrote:
Firstly it looks very neat!!!


Thanks a lot :))

Fudoh wrote:
If the stripper can indeed run on the power coming in from the Scart connection, it would be a shame to ditch this possibility in favor for an external PSU. Can't this be constructed as on the SLG3000, where the IC draws power from the incoming signal and the external PSU is optional (and switchless) ?


I doubt with the current design. LM1881 needs a voltage supply of 5V to 12V. Taking it from the signal is not enough (referring here to my experience with the SLG). Perhaps it`s possible to add some helper components to step up the voltage, Current should be no problem since LM1881 datasheet says it drains only 10mA.

The good part would be that PSU protection is not necessary anymore with such a feature. And there is no need taking power from pin 8 Scart.



Regarding the lm1881's operating at a minimum of 5Vcc ,you could probably substitute it for an LMH1980 or LMH1981 .Those can operate from a supply of 3.3Vcc to 5Vcc (so can be self powered from scart pin 8 )and i think they both output a proper HSYNC and VSYNC,but how much do they cost compared to the lm1881 ?


Last edited by dosucol1 on Wed Jun 22, 2011 1:44 pm, edited 2 times in total.

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 Post subject: Re: Modified CGA to VGA Scaler to accept clean sync RGB SCART
PostPosted: Tue Jun 21, 2011 4:41 pm 



Joined: 02 Feb 2005
Posts: 230
Why not just try an EL1883? It has hsync out, works at 3.3-5V and can replace the LM1881 without redesigning the PCB layout.


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