New yerar, new CPC board

[Piotr]

Idea:
THT technology for self assembly, i use orginal amstrad chips.
Slot's for Toto and my extension boards.
PS2 keyboard interface

So something like this, board drawing almost done.
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To do:  replace 8 DRAM memory chips for one SRAM memory chip and order prototype  board 

[Bryce]

If you are doing a complete re-build I'd advise adding a few other bits, such as onboard voltage regulation to avoid people blowing this up with the wrong voltage/polarity.
It all looks very compact and neat, but have you tried routing this yet?

Bryce.

[Piotr]

Bryce, good question i think add bridge and 2,6 amp voltage regulator. Bridge prevent wrong polarity, voltage regulator do a correct power for all extensions. Yes i have routed board, 4 layers .

[Joseman]

oh my f... god, this is one dream of mine, make a cpc-atx board, 100% compatible with all the original chips!! (as bryce knows )

if this is going to happen, i have only one thing to say: shut up and take my money!!! 

[Bryce]

Oooo, four layers, that will be an expensive PCB  .

A simple diode for polarity protection and a 3A 5V regulator shouldn't be too difficult to add. Are those expansion headers not too close to each other?

Bryce.

[Piotr]

Yeach, 7 USD per board in my China factory.  Dimension 20x13 cm. Is little to close i still working on PCB so is time for good ideas  Diode only prevent connect wrong polarity power supply . With bridge you can connect any polarity power supply.Is more universal i think. 

[Bryce]

If you want to get the size down, then use SMD for the resistors and decoupling capacitors. Maybe consider going SMD for the standard logic too?

Bryce.

[Joseman]

Piotr are you going to make it itx compatible??? please!

[Piotr]

Bryce, idea was make it in DIP (THT) for people who don't have enough soldering skills and equipment but looks for fun to self assembly own board.

Of course i can sit and redraw it for smd 0603 and soic,  solder board using my hot air station,plus flux  run board using my Saleae logic analyzer and Attend digital 100mhz oscilloscope but where is fun?

[Bryce]

Why would you need an oscilloscope and a Logic analyser to run the board?

My suggestions were just to reduce the size. 1206 and SMD LS parts shouldn't be beyond the skills of someone who is willing to solder a board this size themselves.

Bryce.

[Piotr]

Becouse looks like proffesional? Lots of measurment stuff on desk   
For me is easier do it on SMD but i try do something usefull for others, like always i publish project and maybe somebody do it .

Size is important Bruce , but smaller is better?   

Sorry but i have specyfic kind of humor so don't take it very serious, excluding this board project, to be honest i made it for myself becouse standart CPC464 take too many space on my desk, it is like piano.

[Bryce]

I am well  used to French humour and I also make my projects for others to build, but in my experience, even through-hole projects are only made by very few people, the rest of the scene want to buy them assembled.

Bryce.

[TFM]

Looks quite nice! Can on comment on this? If yes...
- A 6128 instead of the 464 would be neat!!!
- The slots of the X-cards are too close to each other, cards will not fit
- Try using bigger RAM chips, the old types are hard to find (even 32 KB is better than 8 KB)
- Adding some more RAM and FlashROM on board would be nice to have


Now it you would like, and this is too much work anyway, you could use discrete chips instead of the GA. The way they did it for the KCc for example.


That's an interesting project, keep it going. 

[CraigsBar]

I want one, take my money lol.

[radu14m]

There is a vga Dsub connector on the boad, right? 
The boards looks great !!!!

I love the ideea of DIY CPC project 

[talrek]

HHHHHHHHHOOO MMMMMYYYYY

I want to be a part of it !!!!!!! I want to assemble, to build, to solder !!!!!!!
Can i help you ?? pleeeaaassse ?

I'm in the top list priority because i'm French too !!!   (French humour inside again.....)

[jrodriguezv]

Hi! I love this project!! I will follow your progress!

[villain]

Will it also be possible to connect a mouse?

[Bryce]

There is a vga Dsub connector on the boad, right? 
The boards looks great !!!!

I love the ideea of DIY CPC project 

I think that's the Joystick Port, not VGA.

@TFM: Making the GA from discrete parts would make the PCB about 6 times bigger!

Bryce.

[Joseman]

There is a vga Dsub connector on the boad, right? 

there is not need for a vga port nowadays, with the new TV and PC monitors the right choice is a RGB to HDMI/scaler conversor like this:

XRGB Mini Framemeister - A PAL torture test

[TFM]

@TFM: Making the GA from discrete parts would make the PCB about 6 times bigger!

Ah no, just check out the KCc and then put it in a small FPGA. Easy does it.

Else... Where do you get the GA from? You're going to slaughter a 464 to build one new on another PCB or what?

[Piotr]

Well i have some GA in my drawer. Canibalize one CPC to made second is a stiupid idea. Problem is i reach maximum pads in my PCB design software so i have two option, divide board for 2 or buy upgrade for 200 euro 
About memory i replace it for one chip. Video out be a standart minidin 8. And i'm Polish, not French. I only living close to Paris from few years.
Anyway, work in progress...
Any mouse interface schematic is aviable?

[Bryce]

Ah no, just check out the KCc and then put it in a small FPGA. Easy does it.

Else... Where do you get the GA from? You're going to slaughter a 464 to build one new on another PCB or what?

That's not what you said earlier, you said:

you could use discrete chips instead of the GA.

Now you are saying "Clone the GA with an FPGA". Which is also a bad idea, because it would mean adding a further ROM and other circuitry. A CPLD clone of the GA would be a nice idea though.

Bryce.

[Joseman]

I think that this must be a 100% preservation board, all the original components included (even the chip ram, 128k's with the 6128 pal)

The boards corrode, the contacts loose, this board with good materials is for a good conservation i think.

i'll only add a ps2 keyboard, a ps2 mouse and a standard db9 rgb port, the expansion ports (like pci ports on pcboard) will bring us the rest... and nothing about dsub ports, with the db9 rgb you can put anything you want with a scandoubler or (better) a rgb to hdmi converter like i said before.

this is not only to canivalize one cpc for this board, because this board bring more flexibility expansions, a little plus with the ps2 ports, if you stay on itx format, you can put it on a mini case, this, a ps2 mouse, a ps2 keyboard and 2 pads is the only you need for gaming and work with the cpc!!

[Bryce]

I'd still include a header for original keyboards for those who intend using it in an original case.

Bryce.