RGB to SVIDEO with A-22 Converter

[crazyegg]

Hi All,

I recently bought this A-22 RGB-SVIDEO converter board from www.arcademvs.com in Canada. The price is pretty affordable at about $25 Canadian.

I was originally planning on using this board with my Commodore 128 in C128 mode with 80 column in 16 colours (using the intensity hack to get the full 16 colours)

However, I am having second thoughts, since I use my Amigas more often.

Is it possible to mod this adapter so as to work with my A1200 or A600? If so, can you post the schematics?

FYI, the A-22 board has the following connections: R-G-B-VSync-HSync-Ground.

Regards,
ed...

[ajacocks]

I'm also interested in this, for similar purposes. However, I'd attach my Apple IIgs, and my Commodore 128.

The IIgs is easy, as it has R, G, B, and composite sync. The C128 isn't _too_ hard, but the wiring of the intensity circuit would be a small challenge.

I use Indivision scan converters in my A1200, and my A3000, so I don't need the RGB adapter on the Amiga side.

[Zetr0]

@crazyegg

The A-22 Converter is for TV's not Monitors

although this should be fine for the A600 - the signals you need are on the back RGB video port.

http://pinouts.ru/Video/AmigaVideo_pinout.shtml (use the analogue colour signals not the digital)

it wont give you any benefit


so please be cautious when buying.

[Zetr0]

Just having a quick lookin on eBay.ca

and I think I have found something that might be of interest -

External CRT VGA PC TV Tuner Box NTSC PAL I B/G AV-In $30CAD Free Postage


This will convert a Composite and SVideo source - de-interlacing (flicker fixing) the incomming signal and scan-doubling to the VGA monitor.

These units are 16 or 18bit I am unsure but there pretty good for most Amiga USE.

now to get the realy benefit from any amiga really you will need to convert the RGB to SVideo (Chroma Y/C)

with the A600 and the A1200 this is done for you, all you need to do is clean the signal and amplify it.

I shall post linkies later =D

[Kakaboy]

Originally Posted by Zetr0

now to get the realy benefit from any amiga really you will need to convert the RGB to SVideo (Chroma Y/C)

with the A600 and the A1200 this is done for you, all you need to do is clean the signal and amplify it.

I shall post linkies later =D

So does this mean we need an adapter from RGB to S-video or can we just make a cable up ?

[Zetr0]

@Kakaboy

for the A600 and A1200 you can use just composite and then upgrade to SVideo later.

the A1200 and A600 have SVideo Y/C from the CXA1145 RGB encoder chip, all you need to do is amplify them, and you will have pretty damn good SVideo out.

in terms of visual output I would say its about 80% that of RGB, in actual bandwidth terms its 66%.

well worth the effort IMHO.

[crazyegg]

Hi Zetr0

Thanks for the pinouts.

So, all I have to do is connect the Amiga output R, G & B Analog, H Sync, V Sync and Standard Ground pins to the respective A-22 input pins and I can enjoy my A1200 in glorious SVIDEO?

PS: If it is that simple, than this thing is similar to the RGB-SVIDEO adapter by amigamaniac.com?

Regards,
ed...

[Kakaboy]

Originally Posted by crazyegg

So, all I have to do is connect the Amiga output R, G & B Analog, H Sync, V Sync and Standard Ground pins to the respective A-22 input pins and I can enjoy my A1200 in glorious SVIDEO?

PS: If it is that simple, than this thing is similar to the RGB-SVIDEO adapter by amigamaniac.com?

Regards,
ed...

Zetro says you need to amplify the signal which is what I assume the Amigamanics adapter does .

[Zetr0]

Originally Posted by crazyegg

Hi Zetr0

Thanks for the pinouts.

So, all I have to do is connect the Amiga output R, G & B Analog, H Sync, V Sync and Standard Ground pins to the respective A-22 input pins and I can enjoy my A1200 in glorious SVIDEO?

PS: If it is that simple, than this thing is similar to the RGB-SVIDEO adapter by amigamaniac.com?

Regards,
ed...

yep, pretty much, but Nathans RGB/SVideo converter is cheaper and IMHO a little better as its an all in one plug-in that allows you to change from PAL/NTSC.

Originally Posted by Kakaboy

Zetro says you need to amplify the signal which is what I assume the Amigamanics adapter does .

Infact it does more. Amigamaniacs SVideo adapter actually encodes the RGB signal from an RGB source... so this will work from an A1000 to and A4000T

however the A600 and A1200 have SVideo Y/C onboard the motherboard you just need to tap those lines and amplift them... this will need a little solder skills, some electronics knowledge and my schematic wen I find it, OR you can say sod it and plumb for an RGB to SVideo Y/C adapter like Nathans

[Kakaboy]

Originally Posted by Zetr0

however the A600 and A1200 have SVideo Y/C onboard the motherboard you just need to tap those lines and amplift them... this will need a little solder skills, some electronics knowledge and my schematic wen I find it, OR you can say sod it and plumb for an RGB to SVideo Y/C adapter like Nathans

I wouldnt mind having a little solder action , I have never soldered anything serious apart from wires

If the parts are easily attainable from my local electronics store than im in !

[Zetr0]

@Kakaboy

its very simple (Bill of Materials)

Resistors
33ohm  [x2]
110k  [x3]
10k   [x3]


Caps (radial electrolitic)
100uf [x2] (C1 and C3)


Monolitic (ceramic)
0.1uf [x2] (C2 and C4)


Transistors
2N3904 [x2]

Simple schematic



if you are unsure take a picture and the recipe with you when you pop into the store, they should be able to help.

[Zetr0]

you can source (YI) Y in "luminescence" from Y out [pin 16] of the CXA1145 chip
you can source (CI) C in "Chroma" from the C out [pin 15] of the CXA1145 chip

[kipper2k]

I have that board in a couple of my A600's. I removed the RF module and placed the Svideo output there. It really does work quite good ans is cheap. Only hard part is soldering pin 15 and 16 to the chip. Keep wires as short as possible too so as to prevent external interference.


edit: one thing you must realise is you can only output colour to the correct region monitor/tv otherwise it will display in black & white

[Kakaboy]

Thanks Zetro man . I will do just that . The resistors direction I am unsure of thou .

[kipper2k]

Originally Posted by Kakaboy

Thanks Zetro man . I will do just that . The resistors direction I am unsure of thou .

Resistors are bidirectional... ( any way you want to place them)

[Kakaboy]

Originally Posted by kipper2k

Resistors are bidirectional... ( any way you want to place them)

Cool was hoping that was the case .

Thanks Kipper

[Kakaboy]

Hey Zetro , Does the single ground output you have in the schematic for both Y & C ? Pin 1 & 2 on the S Video .

[kipper2k]

I'll post a small video later today showing the installation and the picture quality. (Any excuse to use my video grabber

[Zetr0]

Originally Posted by Kakaboy

Hey Zetro , Does the single ground output you have in the schematic for both Y & C ? Pin 1 & 2 on the S Video .

yep its a common ground.

Originally Posted by kipper2k

I'll post a small video later today showing the installation and the picture quality. (Any excuse to use my video grabber

sweet! I look forward to seeing this =D

[kipper2k]

btw, there is someone from this forum that is selling these boards prebuilt, i'll check my old messages and try to find the link


edit:.. hehe, that didnt take too long to google....

http://www.amigaworld.de/hardware/s-video-adapter/

now all i gotta do is find out who


edit 2.... found him... DJBase is who i bought them from last year. price was... 10euro each

the components on that board are surface mount, if you want to build your own, do not get the surface mount, get the components with through hole legs.

[crazyegg]

Hi All,

Thanks for all the insightful replies as usual on EAB!

OK, so I guess that I will use the A-22 adapter for my C128 then as it will be easier...(since I will need to mod or amplify it in order to use it with my A1200).

Thanks kipper2k for the link. 10 euros is very good!

As many are aware, Nathan is out of stock of his RGB-SVIDEO adapter. I have one of his V1 adapters (which I bought off kipper2k; thanks its working great!!) but I would like to get another one for my other Amiga...

Regards,
ed..

[crazyegg]

Hi All,

I noticed that this board design by zetr0 and djbase does not have a NTSC/PAL switch (like Nathan's design). Will this omission be a problem for me as I routinely boot my NTSC Amiga into PAL mode (via holding down the 2 button mouse trick) to play PAL WHDLoad games on my multisystem TV?

Regards,
ed...

[DJBase]

No, it won't. NTSC and PAL will work just fine.

[Zetr0]

both DJBase's adaper and the schematic above output what ever colour-burst-encoding (NTSC/PAL) and frequency (50Hz / 60Hz) that the Amiga outputs.

if you put your PAL amiga into NTSC mode you will get 60Hz PAL
if you put you NTSC amiga into PAL mode you will get 50Hz NTSC

To get true NTSC/PAL colour space from the Amiga you will need another encoder (like Nathans) or some modifications to the Motherbaord.


TV's can be funny things, some will take multiple colour modes (like NTSC/PAL) irrespective of horizontal frequency, where as other are fixed to certain colour modes but can happly shift frequencies. Unfortunately this comes down to the specifications of the TV

from what you state your TV can handle 50Hz screen mode in NTSC colour burst via your current input method.

depending on your TV it may not be able to do this via SVideo Y/C input (try this with nathans adapter)

if your TV could do SCART RGB, I would suggest that above everything else.

[kipper2k]

Heres a video of the svideo homemade board in my A600 and a few oter goodies. I'll put up a video of the actual display quality later tonite.

http://www.kipper2k.com/videos/a600/a600.html

I'll show the connector and the switch when i do the display portion

[Kakaboy]

Originally Posted by kipper2k

Heres a video of the svideo homemade board in my A600 and a few oter goodies. I'll put up a video of the actual display quality later tonite.

http://www.kipper2k.com/videos/a600/a600.html

I'll show the connector and the switch when i do the display portion

Nice ! You going to connect straight to TV via S Video cable ? Look forward to your results .

[kipper2k]

Heres a little vid of the svideo going directly to the TV.. my video grabber doesnt like svideo input, i tried a few devices and it doesnt wanna sync

I used my camera to grab video from the tv. The picture is stable with no wavy lines, the colours are pretty crisp, no fuzzies and none of the ghosting that shows with composite.

http://www.kipper2k.com/videos/poc2/poc2.html

[Kakaboy]

That looks GREAT Kipper !

I'm making mine this weekend , hope it looks as good as yours .

BTW , what is the switch for ? .....EDIT just watched your first video got it .

Where did you tap your +5v from ? & did you use the metal shield as GND ?

[kipper2k]

Originally Posted by Kakaboy

That looks GREAT Kipper !

I'm making mine this weekend , hope it looks as good as yours .

BTW , what is the switch for ? .....EDIT just watched your first video got it .

Where did you tap your +5v from ? & did you use the metal shield as GND ?

yup, i tapped ground from the metal shield and the 5v is tapped from the U33 chip (to the right of the ide header, blue wire). Its a nice easy pin to solder to.

[Kakaboy]

Thanks mate thats great .

[crazyegg]

Hi All,

kipper2k, thanks for the detailed vid! My only fear is soldering the Y and C to the 1145chip. Those pins are very small and close together. Can you offer any tips?

As what zetr0 stated earlier, Nathan's solution is the ultimate complete solution for SVIDEO since it also recodes the colour system to match the sync (i.e. true PAL50 and true NTSC60) so it is "guaranteed" to work on multisystem tvs. But, Nathan is out of stock ;-((.

I was fortunate enough to get an old Sharp Aquos which does support the hybrid modes (PAL60 and NTSC50) which zetr0 and djbase's boards output as stated earlier.

Regards,
ed...

[Zetr0]

@Crazyegg

If you are worried about soldering to those pins on the CXA1145 chip, do you know of an electronics store nearby? They might be able to help. should only take 5 minutes and any charging more than $10 CAD would be criminal so ask about.

At the end of the day you must trust the person thats doing the work for you.

The internal SVideo Y/C boards were made and designed by DJBase - I have one here myself which a friend gave me, its a very VERY nice piece of work and one I am pleased to own

[kipper2k]

I'm kinda disappointed with my hauppauge video capture box, it doesn't want to seem to be able grab S-Video too well. Composite and component work fine but svid does not want to play, not just for the amiga but for the other devices.

does anyone know of a simple way to mabbe amplify the signal a bit? i'm thinking that the signal is just not strong enough when going thru the device to the TC. The amiga works great when going directly to the svid on the TV, and that is true when using the narmi svid output i made and the djbase (CD32) svideo circuit output

A simple circuit, nothing too fancy, just an svid input and output with some means to amplify the output would be great. I seen some multi input/output boxes but i dont want to have to go that route.

[Kakaboy]

My board is different to yours its a rev 1B . Where can I tap my +5v from ? Any ideas or should I just look for anything +5v with multimeter ?

[Zetr0]

@Kakaboy

Take it from U12 (the CXA1145 encoder) Pin 12

[Kakaboy]

Originally Posted by Zetr0

@Kakaboy

Take it from U12 (the CXA1145 encoder) Pin 12

Your a true gentleman Zetro . I have made the board just need to test it .

The RF Module do we just desolder and pull the whole thing out ?

[Zetr0]

unless you want to remove it - it wont cause any harm to be honest.

I will say that removing (I have done this to about 4/5 A1200) is not all that easy, the whole unit acts as a ground plane and will require some hot air, and a good 15 / 20 minutes of effort.


1. start warming up the back of the board at about 300c, keep moving the gun (do this for 5 minutes)
2. increase to 380c and continue for another 5 minutes
3. increase to 440c and contiune untill the solder liquifies.. (pending on your units calibration you may need to krank it to 480c)

Use a solder sucker to remove the solder from the shield anchor pins and and a small terminal screw driver to help gently leaver off the RF unit.

It will take some time and you MUST keep the hot-air gun moving make sure you set your air pressure on low

[cosmicfrog]

hahahah Z you been spoil`d with all ya fanci toys

just desolder the bloody thing and store it away somewhere where you will never look again

[Zetr0]

Originally Posted by cosmicfrog

hahahah Z you been spoil`d with all ya fanci toys

just desolder the bloody thing and store it away somewhere where you will never look again

Indeed I have my friend, I will be honest I wouldn't know what to do without them!!!

alas theres very little chance a 45watt iron will make a dent in the solder of that RF unit. not only does the ground plane of the motherboard act like a giant heat sink sapping heat away, but the RF unit itself also acts like a heat sink.

trying that with a 45 watt iron will only lead to frustration and possibly damaged components.

[Kakaboy]

Originally Posted by Zetr0

unless you want to remove it - it wont cause any harm to be honest.

I will say that removing (I have done this to about 4/5 A1200) is not all that easy, the whole unit acts as a ground plane and will require some hot air, and a good 15 / 20 minutes of effort.


1. start warming up the back of the board at about 300c, keep moving the gun (do this for 5 minutes)
2. increase to 380c and continue for another 5 minutes
3. increase to 440c and contiune untill the solder liquifies.. (pending on your units calibration you may need to krank it to 480c)

Use a solder sucker to remove the solder from the shield anchor pins and and a small terminal screw driver to help gently leaver off the RF unit.

It will take some time and you MUST keep the hot-air gun moving make sure you set your air pressure on low

Thanks mate . I would like to mount the s-video socket in its place . I dont mind leaving it there but cant see where else it would fit ?

Now its important to keep the wires from the encoder chip short right , so does that mean the same for the wires from the s-video board to the connector ?