Making an RGB amp

[soop]

err, I bought some of these, but I'm thinking maybe they're a bit thick?
http://cgi.ebay.co.uk/Mini-Breadboard-Arduino-Prototype-Shield-PIC-AVR-/140549485470?pt=UK_Computing_DesktopComponents_RL&hash=item20b966f39e

I've never really done this before, so I kind of bought the first thing I saw.  Looks nice though.

I bought these to go with them: http://cgi.ebay.co.uk/50pcs-Red-Breadboard-Jumper-Cable-Wires-Tinned-5cm-/290562091870?pt=AU_B_I_Electrical_Test_Equipment&hash=item43a6d9ab5e

Hope they work ok :/  They don't have any of those plug things...

[CGQuarterly]

Breadboards are really for temporary stuff, like making prototypes and whatnot.  If you are making an amp to stick inside a system, you want to just buy a small PC board from a place like Radio Shack.  Those wires are fine, except that for like a dollar you could go to any thrift store and buy a serial or parallel cable and just harvest the wires out of it, which conveniently would be different colors.

Chris

[soop]

Breadboards are really for temporary stuff, like making prototypes and whatnot.  If you are making an amp to stick inside a system, you want to just buy a small PC board from a place like Radio Shack.  Those wires are fine, except that for like a dollar you could go to any thrift store and buy a serial or parallel cable and just harvest the wires out of it, which conveniently would be different colors.

Chris

Cool, thanks Chris.  Admittedly I only looked on eBay, but I just bought the smallest one I could find.  I guess we'll see when it gets here...

[gtsamour]

Here's the one I made...

/dscn0272r.jpg
/pcergb.jpg

[soop]

Woah, that's really useful!  I'm still waiting on the breadboards to arrive, but I have most/all of the other stuff.  I like those input pin things on the far ends, I didn't consider any of that.  If I get stuck, can I drop you a PM? Yours look really good

[gtsamour]

Yeah I've already used these boards in modifying PCEngines to give RGB.
Look here
https://www.pcengine-fx.com/forums/index.php?topic=9299.msg161486
https://www.pcengine-fx.com/forums/index.php?topic=9379.0

The far ends you are reffering to I got from a regular electronics shop, they're very common. Same for the board plate, you get a bigger one and you cut according to your needs.
Yes ofcourse you can PM me for info.

[Charlie]

Ok, here's mine:


Charlie

[nat]

Charlie, you ought to get a few more of these made and sell 'em. I bet you'd have lots of takers.

[grahf]

Don't mind my language, but do you know what would be fucking amazing? A PCB that would fit inside the AV Booster case. You could drill a few holes, and have yourself an OEM looking peripheral (that NEC should have made anyway).

[gtsamour]

I see that the board also contains an amplifier cirquit for the audio channels. Is this necesary? The sound is coming out of the console loud enough, why the need for extra amplification...

What's the eprom chip base for? Flashed game's rom?

[Charlie]

If you're speaking of the RGB booster, it obviously has the R and G and B output already, so you'd probably just want the video. (unless you want the H & V sync's so you can use the VGA connection?).

The audio amps are just buffers, I wanted to protect the TG console.

Prom socket is for, ...well....proms (DUH!).  Actually, if you look closely you can see the four holes in the center; these are to mount the daughter board which is intended to be a EPROM simulator for fast program development (connects to PC for download).  The pins on the daughter board plug directly into the socket.

Charlie

[Bernie]

Yeah Charlie.  If you decide to make these for sale, I am postive people would buy em.  I know I would.

[gtsamour]

I would definitely buy one too if the price was reasonable. Even if it was a simpler and smaller version of it with less jacks.

[soop]

How big is it?  And how do you make one?

[Charlie]

You should be able to estimate the size based on the DIN connector, which obviously fits into the back of the TG.

I ran this sucker on my late-model Sony monitor (on the VGA port).  The result went something like this:
(exagerated to make a point):
Monitor: "I see you have properly formatted Horizontal Sync at 15 KHz"
Charlie "YAY!"
Monitor: "I see you have properly formatted Vertical Sync at 60Hz"
Charlie: "YAY!"
Monitor: "Unfortunately, I can't run that slowly!"
Charlie: "AGGH!"

The RGB and/or Composite video work great (and the audio is a given).  I can run 3 TV's at the same time, if I also use the RF output of the TG itself.

Not too sure it would be cost effective to sell, though.

Don't understand the "how do you make it" question...you lay out a PCB based on the schematic, have it made, buy the parts, and populate it; just like any PCB.   Or did I mis-understand the intent of your question?

Charlie

[soop]

I was talking to a friend about something similar, and he said "you can print PCBs now".  I quickly looked up making PCBs after I saw your thing, but I'd assumed you'd fabricated the board yourself.  I see that it's possible, but it's out of my level.  If you had it made that answers my question just fine.

What I'm thinking now, is that compared to gtsamours it's obviously using smaller components, but I'm thinking it could have been layed out a little neater.  gtsamours looks a lot more economical.  Could be wrong here, but I think that's the case.  It seems to share more connections, and aside from the end connections, it seems to be symetrical vertically and horizontally. [edit] sorry, that's just because yours amplifies more things.  If you recreated gtsamours as a double sided board, it would be tiny.

If this is the case, it should be possible to create a compact, double sided board that takes up hardly any space.  Can anyone else see that?  The problem with the full size components would be that the extra depth would cancel out the decreased width, but with your tiny components, it would be a massive saving in area without an increase in volume.

[Charlie]

Sorry, still not sure what your goal is.

If you want to make the "worlds smallest(?) RGB amp" only , it would fit onto a PCB about 1" square, but you might need to put parts on both sides.
--OR--
if you want to make the "worlds smallest(?) video amp" only, well... it would fit onto a PCB about 1" square, but you might need to put parts on both sides.
--OR--
etc, etc.

Point is, obviously if you remove those functions you don't want, you get smaller!  But my specific goal is the EPROM emulation, so I need socket space...which lends itself nicely to the daughterboard concept I mentioned previously.  And in that case, it makes no sense to design for a fixture to go INSIDE the console (DUH).  But that makes me ask....if RGB is your target, aren't there a number of RGB amps already around here?  And aren't they pretty small already?

Or do you have some other intent?

Charlie

[gtsamour]

soop, from your words I understand that you just want to make an amplifier to fit in a console or something, same as me.

Trust me when I say that the one I made fits just fine inside most PCE consoles. The only exception being the Core II and probably the white PCE, these consoles are so small that i doubt you could ever find something that could fit in there.

My amplifier is symetrical and compacted in a way that it takes the less possible space using these components which I may add cost next to nothing.

I have installed this very design of the amplifier to four PCE consoles and it works like a charm each and every time.

[soop]

soop, from your words I understand that you just want to make an amplifier to fit in a console or something, same as me.

Trust me when I say that the one I made fits just fine inside most PCE consoles. The only exception being the Core II and probably the white PCE, these consoles are so small that i doubt you could ever find something that could fit in there.

My amplifier is symetrical and compacted in a way that it takes the less possible space using these components which I may add cost next to nothing.

I have installed this very design of the amplifier to four PCE consoles and it works like a charm each and every time.

Yes, this is my aim, sorry if that wasn't clear to everyone.  My aim is to make an RGB amp that fits into a Core unit.  I already have the parts already, though it's disheartening that you haven't managed to fit it into the same unit I aim for. I would have thought that the space saved by removing the RF unit on the PCE would have worked :/

@Charlie, I have no idea about the amps out there, I've only just started learning about this.  Do you know of an AMP that could fit into a PCE?  If you could provide a link, I'd apreciate it.

[edit] completely missed the explanation of the daughterboard, yeah, I just want to make an RGB amp, plain and simple, inside a PCE

[Charlie]

Don't know about a CORE unit, but if you simply want a really small RGB unit, there is a schematic someplace here of a simple unit showing 4 transistors.  If you use SMT components and tantalum caps, it should easily fit on a one inch square board.  Since I don't know the abilities of each and every TG unit (I only have a TG-16 and a DUO), I'd first check to see if that same transistor-based circuit actually works on the target unit before making the final PCB.  Next question is, how much room do you actually have in the target unit?  As I said, I am not familiar with the various units, but I'd think that each one should certainly fit a PCB that small --- wouldn't it?

Maybe a better approach would be, tell me how much room you actually have for a PCB (in three dimensions if possible), and I'll see what kind of board will do the job?  Or maybe a picture of the inside of a unit, and we'll see what kind of irregular shaped PCB will fit.  Of course, there is still the matter of installing the connectors, unless you'll accept a cable through a hole someplace.

Charlie

[gtsamour]

Well soop, the Core II i have doesn't have an RF unit to make space by removing (probably only the Core I has one). The Core II produces composite signal. Probably if my amplifier was constructed with tiny components it would be able to fit inside but that would probably require PCB designing and production that I'm not able to do. So I had to go with the external amp solution as you can see in my link above, which isn't bad at all because the amp is relatively small.

The problem resides only in these very small consoles (white PCE and Core). On SuperGrafx, TurboGrafx-16 and  the DUO there is plenty of space, no problems there.

Charlie:
The cosnole soop is reffering looks something like this on the inside https://www.pcengine-fx.com/forums/index.php?topic=9379.0

The simple "just transistors" solution is easy and could probably fit even in the scart but I read somewhere that it can damage the console itself. The rest of the components in the diagram are there for a reason... something to do with regulating impedance if im not mistaken.

Also... all kinds of PCE consoles produce the same output RGB signals so the isn't an issue of the amplifier being suitable for one and not suitable for another. One amp works on all.

[SuperDeadite]

Here's the amp I use.  Absolutely tiny and works wonderfully.

[soop]

That one looks really nice too. Is that a custome PCB?  What are the chips? Are you using those instead of transistors?

[SuperDeadite]

They are DIY kits I buy from a Japanese website.  The pcb is factory made,
I only had to solder in the parts.  It uses IC amps, no transistors.  The
"new N64" amp on gamesx is an exact clone of this circuit.

[gtsamour]

Price and link please....

[SuperDeadite]

About $25 with today's exchange rate.  They will only ship to Japanese addresses though.

[gtsamour]

Hmmm, i think its too expensive. I'll keep making my own amps...

[Charlie]

There are a number of RGB amp threads here, some for op-amps and some for transistors.  In them, the various pros and cons are discussed, including the op-amp type and impedance issues.  (I'm too lazy to find them now, but they ARE here).  I remember specifically that I was the one who guessed what op-amp was actually being used before that info was even published.

$25 is not too much to spend for a pre-fabricated PCB, especially if you consider that the PCB kit is probably a high-volume (= low cost per board) item; the Expansion Interface board I show here, given that it is low-volume (can't get much lower than one!), cost about $150, plus my time in design and component install.  But given, as I said, that both the op-amp circuit and the transistor circuit are available here, just use one of the prototype houses that will make the PCB for $9.99, buy the parts, and build it!

So, anyone want to do some research and determine what size PCB you actually could install in whatever unit, preferably in all three dimensions?  Then let's see what circuitry will fit on it. (Hmm, don't forget you need cable connectors some place!)

Charlie

[soop]

There are a number of RGB amp threads here, some for op-amps and some for transistors.  In them, the various pros and cons are discussed, including the op-amp type and impedance issues.  (I'm too lazy to find them now, but they ARE here).  I remember specifically that I was the one who guessed what op-amp was actually being used before that info was even published.

$25 is not too much to spend for a pre-fabricated PCB, especially if you consider that the PCB kit is probably a high-volume (= low cost per board) item; the Expansion Interface board I show here, given that it is low-volume (can't get much lower than one!), cost about $150, plus my time in design and component install.  But given, as I said, that both the op-amp circuit and the transistor circuit are available here, just use one of the prototype houses that will make the PCB for $9.99, buy the parts, and build it!

So, anyone want to do some research and determine what size PCB you actually could install in whatever unit, preferably in all three dimensions?  Then let's see what circuitry will fit on it. (Hmm, don't forget you need cable connectors some place!)

Charlie

It's a valid point.  Let me see what I can come up with.

[soop]

Although my mini breadboards still haven't arrived, I'm beginning to think that they're wrong for the job anyway, but I also have a bunch of those hole ones coming too.

I've been thinking, and I reckon if I do a double-sided amp, I can get it down to an area of 4x5 holes, which is pretty small, with the power running through the middle, and the ground jumpered from the corners.



It should be like that, but mirrored on the other side.  Can't see why that wouldn't work at the moment (apart from perhaps the size of the components), but any comments?

[gtsamour]

Yes but this way (assuming you'll use regular components) you'll have half width but double hight. I dont see any gain compared to mine. I would suggest against it, the console's case wont close.

[Charlie]

If you want to make a test board that way, it will probably be good enough to let you determine if it is worth making the production board.  (You will find out real fast how critical component layout is when you are working with video signals!)  

If you use SMT components, the tallest parts will be the tantalums; with them on both sides, you're total board thickness will approach .250".  Will a 1"x1"x.25" pcb fit into your available space?  You can get shorter caps, but they qualify as a "speciality" item, and can cost up to $1.00 more each.  

Without knowing the actual space you have available (or it's specific shape), I guess you won't know unit you try it.

Hint: cut a few pieces of standard corregated cardboard box (usually .05" to .10" thick) to the proper shape to drop into your console in the selected area, then stack them up until something hits.  That will give you a close approximation to the allowable PCB length, width and height

Charlie

[soop]

both of you are invaluable.  Hopefully I'll get everything together by tomorrow, but your advice is golden.

[soop]

Ok, I have an update for whover's interested.

I'd probably do it this way again, but I laid them all out on the board, taped over them, and then turned it over to solder, removing legs as I went.
I got it onto a tiny space, about 5x5cm or so.

Then I found out caps have polarity and I couldn't figure out the direction without the legs   Put it to the side for a while after that.  Then I found another way, the stripe on the side, and was

I used solder to make the connections underneath (very tricky for me, it ended up being a bit messy, and I probably used way too much) and some jumper for the ground connections, which go to the outside, with the 5v running through the middle.

Then I wired it up to the expansion port using some coloured wire.

Then I soldered together a scart cable (also very fiddly on the din end, ended up melting through the plastic when a pin got too hot)  after that, I was nearly done.  Everything was wired up, I'd been soldering for several hours straight... and...

Nothing.

Took the multimeter to it, which was more difficult than necessary given the shortness I'd cut the wires to, and I couldn't get a reading from the live (using the ground on the circuit) so it's probably my crappy soldering which has cause the issue.

The next one I make, where I need an "L" connection, or even the 5v all the way through, I might just save a leg ot two and use them as the conduit. And the jumpering for the gound is messy and adds height, I think I'll loop the wires over rather than keep them under.

And the size is fine for fitting in a white PCE thanks to the size difference from the RF to the mini din.

[gtsamour]

If there's no photo it didn't happen

[soop]

As you wish... It's been dremelled obviously:

[gtsamour]

Looks gooood. Did you try to see if it fits into a Core?

[pnauts]

Hello to all, few time ago, I wished make a RGB mod from the elektor schematic (I suppose many of you know about it), I have almost finish all, the only remaining issue is the use of the sync only signal who generating some trouble, but it performs well with Composite using as sync.

/4ckn.jpg
/lbon.jpg
/iu93.jpg

wiring done
/9plh.jpg

RGBS from my scratched lovely Duo.
/n2a5.jpg

The purpose was to use it on my Projector in my dedicated HT room but my projector works with H and V sync separated, so I'll have to use sync separator but I'm confident it will works.

The schematic was originally intended to be used on scart connector (and in this case the sync is done by the composite used as sync in RGB mode).

I'm pretty happy with results, the mainly complaint was for me the artefact scrolling issue, well noticeable on 1st stage in Momotaro Katsugeki, the green moutains with pines showing brighter vertical bars, or the 1st dungeon in Ys.

Happily, the mod solved this and provide more vivid colors and an image accurate.

[thesteve]

Your projector will likely work with 5v c-sync
 2

[pnauts]

no, it can use Csync on its horizontal deflection (from 1Vpp to 5Vpp on 2K2 load according to specs and schematic of the projector, Yamaha DPX-1000), but vertical also needs its own.
I know because I did try by using composite only on HD input and the sync output from my board (H & V) on V input of the projector, I had only little distorsion (probably from the unwanted Horizontal pulse).
I have good hope when I'll have both sync individually to make it works perfectly.
the sync output looks like below for the moment.



on TV with sync by composite (50 ohms load) it works very nice, but with the sync only (2Vpp) I have like a cropping with a little image missing. I'll have to fix it.

[thesteve]

The issue is the huc6260 only puts out 0.3vpp sync 2

[pnauts]

on amp output I had 2vpp and with the sync separator I use now I have my Sync 5vpp.
I have to fix a problem that I encounter sometime on blue I have red flashes and on Red I have blue flashes and no flashes on green.
I'll provide a real Hsync instead of Csync 5vpp to see if it will fix it.

[pnauts]

Here are some pics of the CVBS and the Vsync with 681K Rset on LM1881



According to datasheet, it looks like the Vsync is too long (3H normally -width).
I change Rset and here my results.



live test tonight.
if it fail I wish to use a perfect Vsync instead of CVBS like.

A suivre...

[pnauts]

some many test performed.
I did try some various Rset with LM1881 with there -width sync signal:
182µs
204µs
226µs
234µs
242µs
264µs
272µs
300µs

I just wanted to check what that affect on image, all timing was ko on image.
My projector have also these inputs RGBHV compatible with the component, so I did try what some member did specify, put composite in the Y input and I have the same kind of trouble (some horizontal jitter about 2 pixels).
is the video output from PC engine is 480i with "black line" to fullfill the true resolution of the console (around 240).
I think I couldn't make it works because my projector do not accept such a resolution.
when I'm look at the Csync output by the Huc6260 the timing are a little bit strange when changing from horizontal to vertical (period changing from 64µs to 68µs). Anyway I used a LM1883 and I can see there is a missing pulse on the true Hsync output (I'll post a image).
when I use the software mode (RGB PC) I have no image jitter nor flash color but the image is zoomed.
I think I would have to use S-video as improvment on composite instead of RGB.

[thesteve]

Wow, good eye on the missing pulse
You saw it right
The 240P is the same field sent every scan 30fps 2

[Tatsujin]

ah, those Tex screenies bringing back some oold memories

[pnauts]

Wow, good eye on the missing pulse
You saw it right
The 240P is the same field sent every scan 30fps 2

I'm wondering if this missing pulse is not source of my problem ?
can we talk about a hardware design fault ???
the "funny" thing is that it works with TV with scart input, a digital projector would be definitively more sensitive than old electron beam from analog TV 
Thesteve, I'm not sure of understanding, same field between 2 Vsync in 240p ??
when I use signal in straight mode, the image is centered on screen and the status signal the projector display is 480i, Vsync=15.732 Khz and Hsync=59.97Hz so, I thought that the output of the console was something like:
120 black lines then 240 usefull lines then 120 black lines.
So is XRGB fed with RGBS signal would make the deal and output "another" resolution image to use it on videoprojector ?

[thesteve]

The tv standard was 480i, meaning the tube scanned 240 lines top to bottom, then rescanned with a slight offset to fill in between the lines of the first scan
Most games ran without the offset, causing the scanline effect and twice the frame rate
This worked great on CRT, but digital video processors have issues with it 2

[pnauts]

ok thanks. And about Xrgb ?
could it be a solution ?

[pnauts]

I'd just learn there is /HSync and /Vsync on VDC, I'll give it a try.