Amiga RGB to S-Video + composite adaptor

[kipper2k]

Originally Posted by amigamaniac

@ kipper2k

There is no trimmer or regular cap at all, just a wire from pin 15 on the Amiga RGB to pin 3 on the AD724. This is because the signal from pin 15 is already at the correct required NTSC frequency (theoretically). A cap or trimmer cap is required for a crystal to provide a load, to ensure that the crystal operates reliably at the correct frequency...or something like that

My PCB is larger than yours. It is 5cmx8cm, so it wouldn't fit in that case The RCA and S-Video sockets are PCB mount on my design.

Let me know how you go with it, and thanks for your help!

OMG, i have never heard such currsing and swearing in my household and that was coming out of my mouth!!!. My 3rd
proto drove me crazy trying to build, its one of those dual layer boards and there were so many pins that was
shorted to other pins it was impossible to use. Some of the through holes were open and couldnt be trusted so after
about 2 hours i called it quits and moved back to my first proto. I got rid of the external crystal and set it up
as per your schematic and got garbage!!, i got horrible wiggly lines and no color and a really distorted picture.
I'm sure my boss who lives next door could hear me whining and cursing lol.

ok, so the results, after i swapped the wiring on my first (working) proto around i accidentally shorted pin 3 and 4 on the AD724, to the naked eye it looked like the pads were not shorted. Once i used the alcohol to clean the pads... Voila!!! we have a picture...



On the A500 (NTSC, and LG 50" NTSC Plasma TV) playing City Defence

S-video - i get a minute bit of colour flicker, picture is stable, square, focused and colours are vivid.
rate it 9/10

Composite - a little fuzzy, colours a little washed out (not much), square, stable and colour flicker
rate it 7/10
I also think that the caps are probly due to be replaced too so that could have a bearing on the results


A1200 (NTSC, same TV). playing City Defence

svideo - no colour flicker, picture is stable, square, focused, and colours vivid
rate it 9.75/10
Composite - Damn, stupid wire loose again on the Composite side, i'll rate it later.

[amigamaniac]

@ kipper2k

Thanks mate

Hmmm...so it does work using the clock provided by the Amiga...but the quality of the signal seems to depend on the Amiga too?, which I suspected (feared) may be the case.

How does the picture quality compare between an NTSC crystal, and no crystal - the clock being provided by the Amiga?

I want to make sure that both PAL and NTSC users get the best picture quality possible

If it is superior with an NTSC crystal, I'll add one.

[kipper2k]

Originally Posted by amigamaniac

@ kipper2k

Thanks mate

Hmmm...so it does work using the clock provided by the Amiga...but the quality of the signal seems to depend on the Amiga too?, which I suspected (feared) may be the case.

How does the picture quality compare between an NTSC crystal, and no crystal - the clock being provided by the Amiga?

I want to make sure that both PAL and NTSC users get the best picture quality possible

If it is superior with an NTSC crystal, I'll add one.

I found that my proto with the crystal gave a better quality picture than having no crystal. Having the choice of an external clock would probably ensure the right clock speed on those that may have timing issues. For those few that may have this problem i think it would be good to include the crystal.

[amigamaniac]

@ kipper2k

You've convinced me to go with a second NTSC crystal on my PCB This should get me more sales, as it should now work on any application that outputs RGB, and either HSYNC & VSYNC or CSYNC As I said before, by not soldering on the 23 pin D-Sub for the Amiga, the holes would now be available for soldering wires to, for non-Amiga applications.

@ all

I finished my final design tonight...

It should now convert any (not just Amiga) RGB signal to either PAL or NTSC. There are two crystals onboard, so no external clock source is needed. There is one PCB mounted slide switch, which selects PAL or NTSC colour encoding, and the corresponding onboard crystal (PAL or NTSC frequency). That's it, one switch! Flip it one way, and it gives you PAL output, flip it the other, it gives you NTSC. That is much more user friendly than jumper blocks or DIP switches

Other features:

* Trimmer capacitor for the crystals, as well as two holes for a ceramic capacitor instead, if that works better upon testing.

* Two holes and a silkscreen indicator for an optional 470uF filter capacitor at the +5v in, for non-Amiga users. Perhaps Amiga user's will also find it useful, if they have stinky old caps in their machine, and are getting a bit of noise on the +5v line

*S-Video and Composite outputs - you can use both simultaneously. But why would ya?

* Holes in the corners at the back of the PCB for nylon spacers - this will enable the PCB to be parallel to the desk, level, and not sag. Thus avoiding damage to the connectors.

I got the calculator out and worked out how much it has cost me for all 50 units It was a bit of a shock, and more than I expected. No wonder my credit card is smoking

Anyhow, I'll be selling these adapters fully assembled and tested for AUD$33, not the AUD$30 I was aiming for. This was due to the cost of the extra components. Still not bad I think!

[kipper2k]

Originally Posted by amigamaniac

@ kipper2k

You've convinced me to go with a second NTSC crystal on my PCB This should get me more sales, as it should now work on any application that outputs RGB, and either HSYNC & VSYNC or CSYNC As I said before, by not soldering on the 23 pin D-Sub for the Amiga, the holes would now be available for soldering wires to, for non-Amiga applications.

@ all

I finished my final design tonight...

It should now convert any (not just Amiga) RGB signal to either PAL or NTSC. There are two crystals onboard, so no external clock source is needed. There is one PCB mounted slide switch, which selects PAL or NTSC colour encoding, and the corresponding onboard crystal (PAL or NTSC frequency). That's it, one switch! Flip it one way, and it gives you PAL output, flip it the other, it gives you NTSC. That is much more user friendly than jumper blocks or DIP switches

Other features:

* Tuning capacitor for the crystals, as well as two holes for a ceramic capacitor instead, if that works better upon testing.

* Two holes and a silkscreen indicator for an optional 470uF filter capacitor at the +5v in, for non-Amiga users. Perhaps Amiga user's will also find it useful, if they have stinky old caps in their machine, and are getting a bit of noise on the +5v line

*S-Video and Composite outputs - you can use both simultaneously. But why would ya?

* Holes in the corners at the back of the PCB for nylon spacers - this will enable the PCB to be parallel to the desk, level, and not sag. Thus avoiding damage to the connectors.

I got the calculator out and worked out how much it has cost me for all 50 units It was a bit of a shock, and more than I expected. No wonder my credit card is smoking

Anyhow, I'll be selling these adapters fully assembled and tested for AUD$33, not the AUD$30 I was aiming for. This was due to the cost of the extra components. Still not bad I think!

Yay, you got my vote. So i have to ask the burning question... Whats the ETA on these ?

[amigamaniac]

@ kipper2k

I would guess about 2 weeks. I just have to send the file(s) to the manufacturer. They say it will take about 8 days to make them, then it will probably take 3 days or so to get to me by courier.

I made a .PNG image of my PCB design to show people, but I'm scared to post it in a public forum, because I've spent so much money on this project, not to mention time designing the PCB. Am I just being paranoid? Maybe I should e-mail it to people I trust? Although the AD724 schematic from thier data sheet is simple enough to understand, transferring it to a real PCB with components can be tricky, and requires a lot of thought. I don't want to give someone an "A ha!" moment, that may be stuck on their own design (for commercial use/sale).

You know the feeling, when you create something, you wanna show people!

[kipper2k]

Originally Posted by amigamaniac

@ kipper2k

I would guess about 2 weeks. I just have to send the file(s) to the manufacturer. They say it will take about 8 days to make them, then it will probably take 3 days or so to get to me by courier.

I made a .PNG image of my PCB design to show people, but I'm scared to post it in a public forum, because I've spent so much money on this project, not to mention time designing the PCB. Am I just being paranoid? Maybe I should e-mail it to people I trust? Although the AD724 schematic from thier data sheet is simple enough to understand, transferring it to a real PCB with components can be tricky, and requires a lot of thought. I don't want to give someone an "A ha!" moment, that may be stuck on their own design (for commercial use/sale).

You know the feeling, when you create something, you wanna show people!

I'd sit on it for a while at least until you got it up and working, you don't want someone cutting your grass. Once you sold a few then you may as well show it off as people will reverse engineer it anyway.

I done a design today, i'll email you the pcb to take a peek at. It also incorporates A "Luma trap" which will clean up the composite signal a bit more (only with the AD725). Use ExpressPCB to view it etc. That software is really easy to use, it made doing it fun.

I think i'll try adding component video next, BTW, this is just a "for fun" project for me, i like to keep my brain busy


edit... i sent you the pcb, its a dual layer, and the board size is 1.75" square

[amigamaniac]

@ kipper2k

I'm really only doing it for fun and to keep busy too, otherwise I'd go insane! At the moment I'm unemployed (by choice), as I am about to start studying again full time. It'll be four years of study (at least) to get my degree. I do make a little profit after recouping my costs, which I use to fund new projects, buy more stock for my website etc. It's only possible for me to do it all as a hobby, as the money is just not there to make it a propper business and make a living off it. But that's how I like it

I'm just about to move to a new house too because our landlord put our unit on the market, so I have a lot going on. We're going to look at some houses tomorrow. That's why I wanted to get this project done quickly, so I could then concentrate on other things. I'll still try and squeeze in my other projects if I can after I move and start studying. I think the study load's gonna kill me!

[kipper2k]

Looks like you are gonna be a busy guy. I had 3 years at Tesco's I think most people in the forum will know what that is, then 26 years in the military (Navy) and now 6 years in IT, and still only 35 . If you guys are ever in Churchill and break a leg or something drop in and see me lol. www.churchillrha.com (Oh by the way, you must like snow and cold weather cos there aint no palm trees here).

[amigamaniac]

I just realised posting an image of the silkscreen is fine. It shows the layout of the PCB and components, without giving anything away

I've paid to have 50 PCB's made, and have sent the file to the manufacturer. I'm just waiting to get an ETA from them. I'll post updates as I know more

[Zetr0]

@Amigamaniac

Awesome....

I think I might have a problem..... my eyes instantly filled in all the traces LOL

WHO NEEDS EAGLE ROUTING!!!

it looks great my friend, it truely does.

[amigamaniac]

Thanks Zetty

Apparently the PCB's will ship on the 20th of this month. It will take 2-3 days for them to get to me I guess. So ETA for these demons is two weeks. Two weeks for real this time

My first prototype had two crystals, and switching via that inverter IC and one jumper, as specified in the AD724 data sheet. The picture was shite however. That prototype did have wires all over the joint, so probably suffered from RFI. There was also no ground plane. It was a rush job. The second one had one crystal (PAL), and gave a superb picture on composite. I was not able to enjoy S-Video, due to my equipment, not the prototype I hope that when I assemble the first PCB, the picture is as good as my second prototype!

[ethylene]

@amigamaniac

Congratulations, man, this thing is gonna be real nice. And good luck in the new house!

[kipper2k]

Hi All, Is there any way by modding this svideo output to manipulate the screen size/location of display on the screen by the use of another IC etc. ?

Most TV's nowadays pretty well dont allow this function

@amigamaniac

Men! You're doing a terrific job.
I'd like to order one NTSC board. How should I proceed?

[kipper2k]

Wow,

I went to order me a few more AD724 IC's from Digikey.. And they're all gone!. No more till 6th Aug, good job i found another place

[amigamaniac]

Hi all,

My PCB's have been sent out today, by FedEX! I guesstimate that I'll have them by Wednesday July 22, or Thursday. And since I have all components for all 50 PCB's in stock, its just a matter of soldering once they arrive. And testing of course.

[amigamaniac]

For those people living in countries that don't use 'normal' PAL or NTSC colour standards, I quote the AD724 data sheet directly:

"The STND pin is used to select between NTSC and PAL operation.
Various blocks inside the AD724 use this input to program
their operation. Most of the more common variants of NTSC and
PAL are supported. There are, however, two known specific standards
not supported. These are NTSC 4.43 and M-PAL.

Basically these two standards use most of the features of the
standard that their names imply, but use the subcarrier that is
equal to, or approximately equal to, the frequency of the other
standard. Because of the automatic programming of the filters in
the chrominance path and other timing considerations, it is not
possible to support these standards."

So unless your TV can display true/normal PAL and/or NTSC, you might have issues.

It should also be said that not all LCD TV's will work with the Amiga's output. There's a thread or two about it here on EAB.

[amigamaniac]

Once I have assembled the first unit, and tested it to my satisfaction, I will sell them from my website. Any other way is very inefficient, and time consuming.

I will be updating my website soon, so that people can finalise their purchase in one transaction. At the moment, I send customers a PayPal money request for the correct postage charge separately. Since hardly anyone buys multiple items, I'm going to implement a new system.

Originally Posted by SouthZorro

@amigamaniac

Men! You're doing a terrific job.
I'd like to order one NTSC board. How should I proceed?

[amigamaniac]

Damn! I just entered the tracking number for my PCB's into the FedEX website. It says they could be delivered as soon as Tuesday, July 21! Providing there are no delays.