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avatar_Bryce

Who's interested in having an S-Video Modulator?

Started by Bryce, 14:53, 24 March 11

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Bryce

Having the PCB made is relatively expensive. For a very large batch (especially when the PCB itself is large) then it makes sense to have the PCB made, because making them by hand would just take too long. For small batches it rarely makes sense. And as far as populating the board with parts is concerned, this only makes sense for very very large volumes, because of the costs  associated with setting up the placement machines. On top of that, this particular board is a mix of SMD and regular parts, so it would be stupidly expensive. To get the price down as low as it is now, I would probably have to have several hundred built.

The chemical etching setup I have can handle boards up to 250mm x 100mm, which means I could do about 20 S-VHS boards in one session / evening. With the Megaflash however, I could only handle at most 4 PCBs per session, so a batch of 50 would take weeks (as I only have two evenings per week where I can get stuff done).

The soldering bit doesn't bother me, it's actually a very relaxing pasttime, I usually stick on some music too :)

Bryce.

Devilmarkus

Paid... Cannot wait for it ;)
Then, youtube will be overflooded by videos :D
When you put your ear on a hot stove, you can smell how stupid you are ...

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arnoldemu

Quote from: Devilmarkus on 12:16, 30 March 11
Paid... Cannot wait for it ;)
Then, youtube will be overflooded by videos :D
all of Batman Forever demo  :laugh:
My games. My Games
My website with coding examples: Unofficial Amstrad WWW Resource

Bryce

The adapter supports overscanning, strange frequencies and all the other CRTC tricks out there. So Batman Forever looks great on it :) I tried.

Bryce.

Bryce

Hi All,
      I just added the first connection details to the Wiki page http://www.cpcwiki.eu/index.php/RGB_SVideo , so that you can see how it's connected. But it's a real no-brainer, so anyone should be easily able to connect it up. External only at the moment, but I will add internal connection details later when I have time.

Bryce.

Gryzor


MaV

@Bryce:

Wikipedia tells me that the chroma and luma signal can be joined to produce a composite signal. Your schematic shows an rca jack and a composite pin on the ad724.

Now, while not every tv has an s-video connector, all I've seen in the last couple of years feature composite. Do you have any experience with the picture quality of the ad724 on composite connections?

Right now, I'm trying to figure out which arrangement in my room makes the most sense. If composite is a viable option that'll spare me some work.

MaV
Black Mesa Transit Announcement System:
"Work safe, work smart. Your future depends on it."

Bryce

Hi MaV,
       The AD724 offers an S-Video output and a composite output. The first unit I built had an RCA socket on the board to test the composite. Unfortunately the composite output turned out to be much the same as on the old MP2, rather blurred, because of this, I chose to only have an S-Video output on the final version (the one you will be getting). This definitely gives the best picture quality. So there are several ways to connect the modulator to a TV:

A) Directly to an S-Video input (if the TV has one). Easiest / cheapest / best quality.

B) If your TV has no S-Video but has SCART, then use a SCART adapter  (Like this one  http://www.com-tra.de/img/p/scart_adapter.jpg ) to connect the S-Video Signal (same quality as A). 99% of TVs have S-Video input within their SCART connection (check the TV manual).

C) Use an S-Video to Composite adapter (Like this one http://www.cable-trader.co.uk/images/items/SVHS%20plug%20to%20composite%20RCA%20socket%20adapter.jpg ) to connect to a composite input. This should only be done as a last resort, the quality is nowhere near as good as A or B.

Both adapters mentioned above can be bought for a few cents in most TV shops or online. Other than the quality issues, I also left the RCA off the final version because it makes the circuit more expensive, much bigger and more difficult to install internally.

Bryce.

MaV

Thanks, Bryce!

That'll help getting things sorted out in time for the modulator.  :)

MaV
Black Mesa Transit Announcement System:
"Work safe, work smart. Your future depends on it."

Bryce

Hi All,
      I just added the first internal connection diagram (for the Classic CPC), can someone (who without a diagram would be totally lost) please take a look at this and tell me if it makes sense to them? http://www.cpcwiki.eu/index.php/RGB_SVideo

The points I've chosen on the Mainboard are relatively safe to solder, so even a complete beginner can connect here without fear of damaging their CPC.

Thanks,
Bryce.

Edit: The Plus internal connection diagram has been added now too.

Bryce

I just completely re-did the Wiki page, lots more info there now. http://www.cpcwiki.eu/index.php/RGB_SVideo

Bryce.

redbox

Quote from: Bryce on 10:06, 01 April 11
I just completely re-did the Wiki page, lots more info there now. http://www.cpcwiki.eu/index.php/RGB_SVideo


This is mega, can't wait to put it in my Plus.

Bryce

So the diagrams are understandable enough?

Bryce.

redbox

Quote from: Bryce on 10:32, 01 April 11
So the diagrams are understandable enough?


Sorry, yes, this is what I meant to say - even a cartridge burner like myself should be able to do this  ;)

Gryzor

Great work, man!!! Seems really easy to do anyway.

I haven't ever opened a hole in a CPC's case, what do you reckon would do the job nicely? I do have  (myself or access to) several Dremel accessories...

Bryce

It might sound strange, but for a hole this size (S-Video Socket needs a 12 - 14mm hole) I usually drill a small 1mm guide hole first using a standard metal drill bit, but then the actual hole is drilled using a wood drill bit, with a variable speed drill. Try to keep the drill as slow as possible. The wood drill bit carves away the plastic much neater than a metal drill bit and keeping it slow avoids melting the plastic from heat. Practice on an old piece of scrap plastic first though, before you go and destroy the case or make a really ugly hole. And always check twice and three times that you have chosen the position correctly before you drill anything.

Bryce.

HAL6128

Hi Bryce, thanks for the instructions and all the hints. Pretty good work! Everything is understandable und easy to adapt.
How about the Voltage (5V) of the board / power supply of the monitor? How much capacity is needed? I think about to install beneath the modulator the HxC-SD Floppy Emu (a little mod of Pentagons concept). What do you think?
...proudly supported Schnapps Demo, Pentomino and NQ-Music-Disc with GFX

sigh

Quote from: Bryce on 19:02, 01 April 11
It might sound strange, but for a hole this size (S-Video Socket needs a 12 - 14mm hole) I usually drill a small 1mm guide hole first using a standard metal drill bit, but then the actual hole is drilled using a wood drill bit, with a variable speed drill. Try to keep the drill as slow as possible. The wood drill bit carves away the plastic much neater than a metal drill bit and keeping it slow avoids melting the plastic from heat. Practice on an old piece of scrap plastic first though, before you go and destroy the case or make a really ugly hole. And always check twice and three times that you have chosen the position correctly before you drill anything.

Bryce.

I'm definitely going external! ???

Bryce

Hi hal6128,
         the circuit pulls around 48mA max from the 5V supply. It needs a regulated supply, but so do both the CPC and the HxC, so there should be any problems supplying all of them from one source. If you are using the 5V output of the CPCs original monitor, then there's easily enough amps available for them all.
         As far as physically fitting where you want, you'll have to measure. The PCB is around 42mm long (the Socket protrudes a further 1.5mm at one end. It's approx. 27mm wide and about 18mm high. I say approx. for these dimensions because each PCB is cut individually and might vary slightly. On either side of the socket there are holes suitable for M3 screws, so that you can mount the device securely. The two holes are 19.5mm apart.
          The six pins (for RGB Sync connections etc) are RM2.54, ie: 2.54mm apart, this is a standard for such headers. The small plugs used on PC Motherboards (The ones that go to Speaker / LED / Reset etc) are this size also and might be useful to connect the circuit. If not, you could always solder directly on to the pins.
I'll be adding dimension drawings and further info on the wiki page as soon as I have time.

Bryce.

Bryce

Ok, for those who really like planning things in advance, here's the dimension diagram of the modulator:

Bryce.

Edit: Maybe I should put this on the wikipage too.

OCT

Quote from: Brycejust did a quick calculation and they should cost around 25€ plus postage if I have 10 or more people interested.

Sure enough I'm interested if there's still one available, also preferably with Composite as well.

BTW, while it is hopefully going to be on a Plus in my case (thanks again for the plug&power specifications :)), the "old-gen CPC" leads could be nicely made out of Pollin.de 560341 cut in half I guess (in case the cable does have all 6 pins connected).

Shredder11

S-Video version for me please!  I've not had any luck with all the SCART RGB stuff that I got last year, so this might be just the job.
Amstrad CPC6128, 3.5" Ext' Floppy, SD HxC Floppy Emulator

Bryce

Hi All,
       just so that you know, all parts that I have ordered have been sold already and I haven't any more AD724s. Three people are now on the "waiting list" and three of the original orders have not yet been paid for. So these three will get the three unpaid ones, if they haven't been paid for by the time everything is built and ready to be sent out. I don't intend building a second batch at the moment, but that might change. I'll keep you all informed.

Bryce.

Gryzor


Bryce

Just a quick update, because someone asked "When can I expect mine to arrive" :

The parts ordered from China haven't arrived yet, and I suspect they are probably going to get stuck in customs. Even if they do arrive this week, I won't get a chance to build any before the 17th of this month due to other duties, so don't expect anything to arrive until around the end of the month at the earliest (assuming the parts actually arrive).

Bryce.

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