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I'm releasing my current design for the Amstrad Plus Cartridge PCB.


There is one known issue as far as I'm aware - if you have a reset switch on your Plus machine, there is about a 50/50 chance the board will not initialise properly if not using the Acid option. A power cycle ALWAYS initialises properly. I know there is a fix for this but help has not been forthcoming.


The 2 diagrams attached aught to help with component options for the Acid variant and Non-acid variant. Obviously you will always need an eprom. I have labelled on the silk screen what components go where so it should be easy to sort out.


The ZIP file contains both the eagle design schematics and the board layout file, so people who like to tinker can. There is a sub folder called "gerbers" which you can just upload to your PCB manufacturer of choice to get them produced. I've tried both JLCPCB and Seeed Studio Fusion with great results.


Enjoy!

Cool! Any project with it?  :)
Yes, the no acid design (nocash) have this known problem.

Very nice of you to provide this to the community.

Excellent work.

Thank you.
Cheers,
Shane

Quote from: TotO on 10:39, 27 May 19
Cool! Any project with it?  :)

No projects - all my project seem to reference the wrong items anyway  ;D  (Eagle noob)

Quote from: TotO on 10:39, 27 May 19
Yes, the no acid design (nocash) have this known problem.

I've heard there is a workaround, but I've had no joy in finding this out. I use these for GX4000 stuff anyway, so no great harm.

Quote from: Chinnery on 11:31, 27 May 19
No projects - all my project seem to reference the wrong items anyway  ;D  (Eagle noob)
I've heard there is a workaround, but I've had no joy in finding this out. I use these for GX4000 stuff anyway, so no great harm.

The workaround would most likely involve taking the reset signal to the cartridge which wouldn't be praticle or at least mean modding the CPC.

Bryce.

Thanks to @Chinnery (http://www.cpcwiki.eu/forum/index.php?action=profile;u=2434) for providing the Gerbers, I had a batch of boards made up just for fun.

I have just finished 5 boards for my own 'Arcade Classics" collection, and they work perfectly.

Cartridges made:                                                  EPROM USED:
1)Frogger - The 'Executioner' arcade port 2007          M27C2001
2)Ghosts'n Goblins GX4000 - Xifos 2018                    M27C2001
3)Space Invaders Arcade Emulator - 40Crisis 2016     M27C2001
4)Bomb Jack I - Phantomz conversion update             M27C4001
5)Scramble - PuzCPC 2019                                        M27C4001

Next plan is to get some 3D printed cases made up, and put some stickers on them to make them appear somewhat professional.

[attach=1,msg175498]

Cheers,
Shane

How long till copies of Pang and Chase HQ XIII appear on ebay? :D

Quote from: Gryzor on 14:22, 24 June 19
How long till copies of Pang and Chase HQ XIII appear on ebay? :D

Good point, I'm sure people would like to see Chase HQ 2 appear, one day maybe one day.....

Just wondering if you have managed to create a STL for a case for these cartridges? I have got a few PCBs and awaiting parts to assemble - any idea if there is enough clearance for a ZIF socket?
Cheers,
Antony

Quote from: 00WReX on 08:44, 23 June 19
Thanks to @Chinnery (http://www.cpcwiki.eu/forum/index.php?action=profile;u=2434) for providing the Gerbers, I had a batch of boards made up just for fun.

I have just finished 5 boards for my own 'Arcade Classics" collection, and they work perfectly.

Cartridges made:                                                  EPROM USED:
1)Frogger - The 'Executioner' arcade port 2007          M27C2001
2)Ghosts'n Goblins GX4000 - Xifos 2018                    M27C2001
3)Space Invaders Arcade Emulator - 40Crisis 2016     M27C2001
4)Bomb Jack I - Phantomz conversion update             M27C4001
5)Scramble - PuzCPC 2019                                        M27C4001

Next plan is to get some 3D printed cases made up, and put some stickers on them to make them appear somewhat professional.

 

Cheers,
Shane

Quote from: BeaglzNZ on 23:59, 23 August 21
Just wondering if you have managed to create a STL for a case for these cartridges? I have got a few PCBs and awaiting parts to assemble - any idea if there is enough clearance for a ZIF socket?
Cheers,
Antony

There's definitely not enough space for a ZIF socket. Even a standard low profile IC socket will require a hole in the lid for the IC to poke through.

Bryce.

There one STL on Thingverse for normal Cartridge.


quite easy to modify. Will have a look next week.


Done - the bottom is the same that is avalaible on Thingverse thanks to Wolfiem.
The top has 2 versions : Hole to seen the eeprom and change it without opening the cartridge / hole covered otherwise.

+

I took it on to design a shell that's a bit closer to the original. There are some compromises due to FDM printing limitations and laziness, so it's a little bit boxier than the original and the details aren't all 100%. Biggest/most obvious changes are that the front and back sticker recesses are marked out but not recessed as that makes them near-impossible to print well, and the sides of the cart aren't tapered. Smaller differences are that the bottom edge also isn't tapered and the grips are a little different because it's impossible to print that detail with a 0.4mm nozzle.

This should be printed with the flat surface on the print bed and with supports everywhere. They print side-by-side fine and with my personal settings, it's a bit under a 4-hour print. It's designed to be printed with a 0.4mm nozzle and 0.2mm layer height. Once support is cleared, the pieces will snap together - if you're lucky, you can also pry them apart, but that may break the clasps (done it a few times here and no breakages yet, but that surprised me). Enjoy!

Somewhere else I've written that already.


after analyzing the oszillograms from octoate and nilquader in the past I found a solution for the reset problem with a simple rc-combination on the preset pin.
I never had any issues with a cart using this and I always use a reset-key.

I've attached my Eagle project (Sch/Brd) should anyone wish to implement Shining's reset fix. If you do and it tests well can you please repost back here? (I have no plus machine to test with)

Quote from: Shining on 14:10, 28 August 21
Somewhere else I've written that already.

after analyzing the oszillograms from octoate and nilquader in the past I found a solution for the reset problem with a simple rc-combination on the preset pin. I never had any issues with a cart using this and I always use a reset-key.

I have tested this schematic by curiosity, and it looks to not work at all. ;D

May be I have done something wrong...
I don't understand what does special your RC combination compared to the original schematic.

Somebody know this cartridge

https://twitter.com/anakintf/status/1459907093780217856 (https://twitter.com/anakintf/status/1459907093780217856)

Well... It is probably the C4CPC grandfather. ;D
Nothing official here, despite the Amstrad logo.

Quote from: ChrisJames on 14:14, 05 December 21
Somebody know this cartridge

https://twitter.com/anakintf/status/1459907093780217856 (https://twitter.com/anakintf/status/1459907093780217856)

Looks like a cartridge with a flash instead of eprom.
The red/black wire are used to carry WEN/OEN to the cartrige PCB (these are not wired to the cartrige connector).

So it's a nice way to avoid unplugging the flash from its socket when you need to reflash it.

Quote from: TotO on 19:52, 05 December 21
Well... It is probably the C4CPC grandfather. ;D
Nothing official here, despite the Amstrad logo.

It looks something similar to what you want to do with the PLAY2CPC  8)

It seems easier to have a cartridge PCB with a ZIF socket for development.

Quote from: ChrisJames on 22:31, 05 December 21
It looks something similar to what you want to do with the PLAY2CPC  8)

The Play2CPC allows to write the cartridges directly from the CPC.
It is more close to what is doing the X-MEM or the good old CTC-AY project.

Just wondering what thickness do you use for the PCBs? I got some done at the default thickness which is 1.6mm I think but it seems a bit too thick?
Thanks.

1.6mm is the correct thickness. The card pins need to make good contact.


Bryce.

Quote from: BeaglzNZ on 02:31, 11 December 21
Just wondering what thickness do you use for the PCBs? I got some done at the default thickness which is 1.6mm I think but it seems a bit too thick?
Thanks.

Are you willing to sell one? Looking to create a demo, and if I can't get a C4CPC, one of these would be the back up plan

Quote from: TotO on 16:58, 03 December 21
I have tested this schematic by curiosity, and it looks to not work at all. ;D

May be I have done something wrong...
I don't understand what does special your RC combination compared to the original schematic.

Perhaps my schematic was not clear, cause I missed to describe the signal on the RC-combination:


On the original oscillogram for acid reset (https://www.cpcwiki.eu/index.php/File:ACID_Init_by_Grim.png (https://www.cpcwiki.eu/index.php/File:ACID_Init_by_Grim.png)) you will notice that after startup the sin signal has to be high. Using the original schematic from nilquader, the sin signal after reset is 50% low or high cause it does not follow the reset at all. Now instead of pulling the RC to VCC, I used the CCLR signal not only for CLK+ but also for PRE at the flip flop to force the flipflop to "1" after reset. Also I lowered the time constant for the RC-combination.


I know quite some plusses where this always works and noone reported a single problem until now.

Hi Shining,

Please, can you show it working?
I have tested and it doesn't work for me.

Thank you.

I use one of these all the time. It has always worked fine with any machine I tried it on.

Bryce.

My skills in soldering a fairly poor and I have no background in electronics, but I successfully managed to build me a working Batman the Movie cartridge. Thanks for sharing this project!
(https://forum.tlienhard.com/phpBB3/download/file.php?id=12991)
What I´m still struggling with: I was always under the impression that the ACID chip was always required to use a cartridge on the GX4000 and those chips are hard to get these days. How come this project lets you decide whether to run with or without the ACID chip?

Quote from: schombi on 06:53, 09 January 22
My skills in soldering a fairly poor and I have no background in electronics, but I successfully managed to build me a working Batman the Movie cartridge. Thanks for sharing this project!
(https://forum.tlienhard.com/phpBB3/download/file.php?id=12991)
What I´m still struggling with: I was always under the impression that the ACID chip was always required to use a cartridge on the GX4000 and those chips are hard to get these days. How come this project lets you decide whether to run with or without the ACID chip?

The 74HC112 is setting the appropriate signals at exactly the right time, so the CPC thinks there's a valid ACID chip on the board.

Bryce.

Many thanks! Has this been only discovered "recently"? Seems like a pretty simple solution. I always thought a more complex workaround (e.g. a CPLD) was required.

There's a flaw in the ACID design that's being exploited - the CPC signals that the input from the 'ACID' is wrong long enough before forcing a reset that you can flip the input you're supplying (via the '112) to make it happy again.
https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/acid-chip-inside/msg22291/#msg22291 (https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/acid-chip-inside/msg22291/#msg22291)

Cheers!  :)

Quote from: Shining on 09:55, 05 January 22

Quote from: TotO on 16:58, 03 December 21I have tested this schematic by curiosity, and it looks to not work at all. ;D

May be I have done something wrong...
I don't understand what does special your RC combination compared to the original schematic.

Perhaps my schematic was not clear, cause I missed to describe the signal on the RC-combination:


On the original oscillogram for acid reset (https://www.cpcwiki.eu/index.php/File:ACID_Init_by_Grim.png (https://www.cpcwiki.eu/index.php/File:ACID_Init_by_Grim.png)) you will notice that after startup the sin signal has to be high. Using the original schematic from nilquader, the sin signal after reset is 50% low or high cause it does not follow the reset at all. Now instead of pulling the RC to VCC, I used the CCLR signal not only for CLK+ but also for PRE at the flip flop to force the flipflop to "1" after reset. Also I lowered the time constant for the RC-combination.


I know quite some plusses where this always works and noone reported a single problem until now.

So for clarity, the RC combination is not being pulled to VCC but instead is tied to CCLR? Sorry for being dumb.
I built one of these with the R1 connected to VCC AND CCLR. Didn't work obviously and I presume it's because the RC combo is not able to do its thing (as it's pulled high always.

Cheers.

So is this the correct interpretation of what 'Shining' posted?
I've connect the top of the R1 to CCLR and CLK (R1 is no longer connected to VCC). I've changed C2 to 100pF.

Initially I tried a 74HC112 flipflop but read somewhere that it should be a 74AC112 as the other is too slow, which seems to contradict the success others show in their posts. Regardless I am now using a  74AC112N and it's still not working.


I spent time last night double checking my PCB against this schematic and it's correct as far as I can tell. I then started modifying it to see if I could try different interpretations of the info presented in this thread but I just can't get it to work no matter what I do.GX4000.png


Of course I have no real proof that the EPROM is flashed correctly, but I do know that 'EGecu Pro' verifies the EPROM against the ROM and shows it is correct.  Is there any trick to flashing the EPROM? I downloaded a bunch of BIN format ROMS from CPCMania and burned them (I've tried several). I also tried CPR format files (which I converted to BIN using CPRTools) but all I get is a black screen on the TV.

Nobody can help??

Do you have a working original cart?  Maybe you could take the EPROM from there.  There are a couple of cartridge designs knocking about that work fine with the 74ac112

Thanks for your reply. I do have a working copy of Burning Rubber that I could use in my circuit which could help with fault finding, but I'd rather not dismantle the case to access the ROM. I was hoping somebody could confirm my understanding of what Shining had posted and maybe take a look at my schematic.

I'm not sure what schematic software you are using, but it looks like the VCC pins aren't connected to the IC's. I assume they are on your prototype board?

Bryce.

Hi Bryce, thanks for responding.

I'm using EasyEDA to do the schematics and I do have VCC and Gnd connected to each of the ICs on the prototype board. 

My question is really about how R1C1 are connected. At the moment I have the top end of R1 connected to CCLR (as is the CLK for U2). Does this look about right? 

hi i'm trying to make this cartridge work without the chip acid
but without modifications it does not start on my cpc 464 plus what should I modify on the card that I did print?
do i have to do some sanding?
I am sure that the eprom written by me work because if I put the chip acid they start without problems
can someone just tell me the modicum to do?

Quote from: bobmoo79 on 12:25, 30 June 22So is this the correct interpretation of what 'Shining' posted?
I've connect the top of the R1 to CCLR and CLK (R1 is no longer connected to VCC). I've changed C2 to 100pF.

Did you ever get that to work? I want to implement the same design but I'm not sure if it's correct or not.

Quote from: bobmoo79 on 12:25, 30 June 22Initially I tried a 74HC112 flipflop but read somewhere that it should be a 74AC112 as the other is too slow

Can someone confirm that the 74AC112 is required? Or should the 74HC112 always do? Or: in which cases is the 74HC112 not sufficient? I have a cartridge here with a HC112 and it seems to work.

The hack is exploiting a race condition, so while HC-series logic *might* work, it might also be marginal, fail altogether, or depend on the input voltage, ambient temperature or phases of the moon. So you'd want to be at least prepared to switch to a faster series like AC if you experience problems.

I have only used the 74HC112, and had no issues at all.

Hello,

I use 74HC112 and it perfectly work for me as well.
IMG_2035.jpg

Quote from: eto on 10:02, 05 January 23

Quote from: bobmoo79 on 12:25, 30 June 22So is this the correct interpretation of what 'Shining' posted?
I've connect the top of the R1 to CCLR and CLK (R1 is no longer connected to VCC). I've changed C2 to 100pF.

Did you ever get that to work? I want to implement the same design but I'm not sure if it's correct or not.

Quote from: bobmoo79 on 12:25, 30 June 22Initially I tried a 74HC112 flipflop but read somewhere that it should be a 74AC112 as the other is too slow

Can someone confirm that the 74AC112 is required? Or should the 74HC112 always do? Or: in which cases is the 74HC112 not sufficient? I have a cartridge here with a HC112 and it seems to work.

Hi ETO, no I didn't get my carts working in the end because life got in the way and I didn't get clarification in this thread about what the schematic actually is. From the other replies it seems the choice of IC is not a concern. I still intend to go back and revisit this at some point though, so would be interested to know if you get yours working (and how).

@Kris as yours work fine are you able to clarify the design, addressing my previous queries?
Could you post your design/schematic file here so that we can open it in our own software to check against our own?

Quote from: bobmoo79 on 13:08, 05 January 23so would be interested to know if you get yours working (and how).

I didn't have a 100p capacitor yet - they should arrive in a few days. But I got curious now and tried it with a 470p capacitor that I had here. Seems it works. I tried it on two different 6128 Plus machines and had no problems. Also Reset works.

I compared our schematics and can't find a difference... so no idea why it's not working for you.

I'm using a 74AC112 at the moment

I just incidentally found the 74F112 (TTL) which are new old stock and MUCH cheaper than the AC112. They are also much faster than the HC ICs.

Are there any reasons why they could be a bad idea?

In my current design I will add some flexibility, so a single PCB can be used for 1Mbit up to 8Mbit Eproms and also offer the option to add DIP switches to select different ROM images, if an Eprom holds more than a single ROM image. 

You can basically use it for anything from 64KB to 512KB ROM images and 1Mbit to 8Mbit Eproms.

My personal use case is to have a single System cartridge for my Plus that holds everything I could ever need, but of course you can also use it as a multi-game cartridge.

Btw: For this use case I just read yesterday on Facebook that a Multicartridge is available again. It's almost twice as big as a normal cartridge but can also hold two 8Mbit Eproms, which gives you access to e.g. 16 (original) games: https://github.com/zeus074/Amstrad_Multicart?fbclid=IwAR1Y5acw2JXlD7Lj_-oVmmmFXKxp1TZOorqEduaN-04Ssz4G5vX5jw_AjnA

Quote from: eto on 12:41, 06 January 23En mi diseño actual, agregaré cierta flexibilidad, por lo que se puede usar una sola PCB para Eproms de 1 Mbit a 8 Mbit y también ofreceré la opción de agregar interruptores DIP para seleccionar diferentes imágenes ROM, si un Eprom contiene más de una sola imagen ROM.
Básicamente, puede usarlo para cualquier cosa, desde imágenes ROM de 64 KB a 512 KB y Eproms de 1 Mbit a 8 Mbit.
Mi caso de uso personal es tener un solo cartucho System para mi Plus que contenga todo lo que pueda necesitar, pero por supuesto, también puede usarlo como un cartucho multijuego.

Por cierto: para este caso de uso, acabo de leer ayer en Facebook que un multicartucho está disponible nuevamente. Es casi el doble de grande que un cartucho normal, pero también puede contener dos Eprom de 8 Mbit, lo que le da acceso, por ejemplo, a 16 juegos (originales): https://github.com/zeus074/Amstrad_Multicart?fbclid=IwAR1Y5acw2JXlD7Lj_-oVmmmFXKxp1TZOorqEduaN-04Ssz4G5vX5jw_AjnA
 
Hello, does this design allow 74HC112 or is an original chip necessary? Can you share PCB file? Thanks!

Hello, does this design allow 74HC112 or is an original chip necessary? Can you share PCB file? Thanks!
First design works perfect for me with MC74HC112N

Quote from: Duca750 on 18:54, 08 January 23Hello, does this design allow 74HC112 or is an original chip necessary?

74??112 - I have to confirm yet, if HC will work or if AC or F is required. I have ordered a set of ICs, so I can test that soon. 

I have not yet tested the final design and I need to check if it fits into any of the available 3D printed cases or if I have to adjust the design. A couple of weeks probably before I can release the PCB. 

An HC chip works fine, I've tried it.

Quote from: tjohnson on 00:09, 09 January 23An HC chip works fine, I've tried it.

Also with Shinings modified circuit? Or just the original NoAcid?

Quote from: eto on 23:56, 08 January 23

Quote from: Duca750 on 18:54, 08 January 23Hola, este diseño permite 74HC112 o es necesario un chip original?

74??112 - Todavía tengo que confirmar si HC funcionará o si se requiere AC o F. He pedido un conjunto de circuitos integrados, así que puedo probarlo pronto.

Todavía no he probado el diseño final y necesito comprobar si encaja en alguno de los casos impresos en 3D disponibles o si tengo que ajustar el diseño. Un par de semanas probablemente antes de que pueda lanzar el PCB.

Estoy esperando nuevas noticias. ¡Gracias!

Quote from: eto on 23:56, 08 January 2374??112 - I have to confirm yet, if HC will work or if AC or F is required. I have ordered a set of ICs, so I can test that soon. 

fyi: I have tested a previous version of the PCB with Shinings modification of the NoAcid with 74xx112 of type ACT,AC,HC,HCT and F. All work. Reset also works. 

New PCBs haven't arrived yet, so it will still need some time until I can test the final PCB layout. 

Quote from: eto on 01:15, 15 January 23

Quote from: eto on 23:56, 08 January 2374??112 - I have to confirm yet, if HC will work or if AC or F is required. I have ordered a set of ICs, so I can test that soon.

fyi: I have tested a previous version of the PCB with Shinings modification of the NoAcid with 74xx112 of type ACT,AC,HC,HCT and F. All work. Reset also works.

New PCBs haven't arrived yet, so it will still need some time until I can test the final PCB layout.

I find that stability with expansions is greatly affected using these carts - the usifac in particular is completely unusable with anything except the stock basic cart. It'd be neat to test expansions with these various chips too, to see if any are more stable than the others...

Quote from: Cwiiis on 12:42, 15 January 23the usifac in particular is completely unusable with anything except the stock basic cart.

What happens with the Usifac? Lock during boot after the initial messages appear on screen?

I can test later today if I have similar issues or if any of the chips works better than the other. 

Quote from: eto on 13:00, 15 January 23

Quote from: Cwiiis on 12:42, 15 January 23the usifac in particular is completely unusable with anything except the stock basic cart.

What happens with the Usifac? Lock during boot after the initial messages appear on screen?

I can test later today if I have similar issues or if any of the chips works better than the other.

Yes, lock-up on boot or if it gets further than that, lock-up during |help output. On my 6128+ with tape port, it also often triggered the tape relay and "Press return to play" message.

Quote from: Cwiiis on 13:07, 15 January 23Yes, lock-up on boot or if it gets further than that, lock-up during |help output. On my 6128+ with tape port, it also often triggered the tape relay and "Press return to play" message.

I tried it with several variations. In no variation I had a lock during boot.

However I could only start a game with a single cartridge: This is an original cartridge with EPROM replaced and Parados installed.

With all other cartridges I can select an image but once FDC emulation is activated, the system locks. Original BASIC cartridge or cartridge with NoAcid behave identical. No difference between HC, AC and F.

Since we have a similar issue on some CPC464s, where it locks during boot after firmware is initialised I got the idea that the Usifac maybe issues the ROMDIS signal slightly too late, so that a fast ROM/Eprom already outputs data to the bus and then the Usifac also outputs data to the bus. Not sure if that is a valid idea.

Quote from: eto on 14:31, 15 January 23

Quote from: Cwiiis on 13:07, 15 January 23Sí, bloqueo durante el arranque o, si va más allá, bloqueo durante la salida de ayuda. En mi 6128+ con puerto de cinta, a menudo también activaba el relé de cinta y el mensaje "Presione volver para reproducir".

Lo probé con varias variaciones. En ninguna variación tuve un bloqueo durante el arranque.

Sin embargo, solo pude iniciar un juego con un solo cartucho: este es un cartucho original con EPROM reemplazada y Parados instalado.

Con todos los demás cartuchos, puedo seleccionar una imagen, pero una vez que se activa la emulación FDC, el sistema se bloquea. El cartucho BASIC original o el cartucho con NoAcid se comportan de forma idéntica. No hay diferencia entre HC, AC y F.

Dado que tenemos un problema similar en algunos CPC464, donde se bloquea durante el arranque después de que se inicializa el firmware, tuve la idea de que Usifac tal vez emita la señal ROMDIS un poco demasiado tarde, por lo que una ROM/ Eprom ya envía datos al bus y luego Usifac también envía datos al bus. No estoy seguro si esa es una idea válida.

Hi! new PCB received? You can test ? Thank you!

Quote from: Duca750 on 17:05, 18 January 23Hi! new PCB received? You can test ? Thank you!

No, they will arrive within the next couple of days. But I am also waiting for the 8Mb Eproms which haven't shipped yet (probably due to Chinese new year) and are confirmed for delivery mid of February. Once they arrive I can work on that again. I will update the thread once everything is here and tested. 

I am testing with its original cartridge to make a cartridge with 4 Rom with M27C4001.  At the moment the cartridge boots, but I don't understand why I select the option I select, the first ROM always comes out.  For this adaptation, I have cut the tracks where I have soldered the DIP, only the area is used as a support.PhotoPictureResizer_1674065304315_copy_640x853.jpg PhotoPictureResizer_1674065332285_copy_1200x1600.jpg

Quote from: Duca750 on 19:23, 18 January 23I am testing with its original cartridge to make a cartridge with 4 Rom with M27C4001.

Seems good to me. Not sure what is wrong there. Which four ROMs have you been using?

If it's just for that particular use case you can find attached the Gerber files for my proof of concept for a cartridge PCB. It's the one where I tried out Shinings No Asic patch and this works for me. I can't guarantee of course that it works for everyone.

With this PCB you can burn four 128K Roms on a 4Mbit Eprom and select with dip switches. Just add the Dip switch and 10K resistors to the PCB. 

(You can also use this PCB with a 512K Rom. In that case, don't populate the DIP, don't add the 10K resistors, but close the bridges below the 10K resistors. Two 256K Roms will also work. In that case only populate the upper most DIP, add one 10K resistors a the position marked as A18, don't add the other resistor (A17) but close the bridge below that resistor. )

Indeed, it's just a test that I wanted to do, ROM 1: burnin rubber+Basic, ROM 2: I think I remember Parados+Basic, ROM 3: Batman and ROM 4: Robocop 2. I'm not good at electronics, a friend from another forum told me I make this scheme, can you confirm if it is correct?  In any case, thank you very much!
Screenshot_2023-01-18-23-17-59-466-edit_com.miui.gallery.jpg

Quote from: eto on 23:56, 08 January 23

Quote from: Duca750 on 18:54, 08 January 23Hola, este diseño permite 74HC112 o es necesario un chip original?

74??112 - Todavía tengo que confirmar si HC funcionará o si se requiere AC o F. He pedido un conjunto de circuitos integrados, así que puedo probarlo pronto.

Todavía no he probado el diseño final y necesito comprobar si encaja en alguno de los casos impresos en 3D disponibles o si tengo que ajustar el diseño. Un par de semanas probablemente antes de que pueda lanzar el PCB.

¡Hola! ¿Podría realizar las pruebas con este nuevo cartucho? ¿Con qué chip 112 es compatible? ¡gracias!

Reviving this old thread... any news on this topic?

I made a new version of the PCB which is more flexible regarding ROM image size and EPROM size.

You can select the ROM image size by creating shorts on the PCB and if your EPROM is bigger than the ROM size, you can use dip switches to select the ROM number. It was originally meant to support even 8MBit ROMs (so up to 8 of the original GX4000 games on a single normal sized cartridge) but I made a mistake there, so although it theoretically is possible, at the moment it requires to cut a trace and solder one wire. I will fix that eventually and then release the Gerbers and 3D printing files for the cartridge case.


Based on that PCB in the meantime also made a "developer" cartridge for my personal use. It's big enough so you can change the EPROM while the cartridge stays inside the Plus. ROM size and number is adjusted by switches or jumpers. You can have 64KB to 512KB ROM image sizes and 1MBit to 8MBit EPROM sizes. It's quite convenient e.g. to have diagnostics and several OS versions on the same cartridge and just need to select the right one.

Quote from: eto on 08:26, 27 September 23I will fix that eventually

AAAAAAND fixed... 

I just ordered the new PCBs

Looks lovely  8)

I am working atm also on a cartridge project and my first prototype PCBs but there is still much work to do.  ;)

Hello Eto, excellent work. Is this PCB functional?...I would like to try creating a cartridge...
(https://www.cpcwiki.eu/forum/index.php?action=dlattach;attach=38590;image)

Quotetested a previous version of the PCB with Shinings modification of the NoAcid with 74xx112 of type ACT,AC,HC,HCT and F. All work. Reset also works

Similar to bobmoo79 I've had trouble with the 'shining' version. My approach was modifying existing working Chinnery 2.10.1 cartridges (still using 74HC112N)

Steps were:
1. Cutting the R1 (4.7K) line from VCC and routing CCLR
2. Changing C1 from 100nf (104) to 0.1nf (101)

The results are the CPC464 plus starts but with white green or partial graphics on the cart. I've reverted Step 1 of the 'Shining' changes and the games start fine

Be interested to try the Eto version when that is available 

Pictured are the modifications. Any ideas on this one?

Quote from: destroyer on 11:35, 21 November 23Hello Eto, excellent work. Is this PCB functional?...I would like to try creating a cartridge...

I made several cartridges with it and it works on my GX4000 and Plus 6128. However the most recent version is more flexible.

Quote from: darkhalf on 05:05, 09 December 23Be interested to try the Eto version when that is available 

Sorry, I was moving house and the CPC stuff did not have priority. I hope I will be able to test the latest PCB within the next few weeks and then document and publish it. But most likely after Christmas.

Generally speaking it works (previous version with just a slightly different layout was tested with GX4000 and 6128 plus) and can hold up to eight 128K images in a single Eprom, selectable with DIP switches. 

Just a note, I've updated my cartridge case design - I strongly advise not using the old model, there isn't really enough space inside for the PCB with an EPROM soldered (it's about 0.3mm too narrow). PLA is flexible enough that this doesn't matter too much, but it will introduce problems with more rigid printing materials (like resin). This updated design is very close to the original; of all the reproductions I've seen, I believe it to be the closest, and it remains a feasible print with FDM. It has more than enough room for a soldered PCB inside and a good amount of tolerance if you don't solder the EPROM completely flat - this room was made by narrowing the walls, which also makes it a cheaper print.

Model files, details on where you can get it printed, etc. are available on the Thingiverse page: https://www.thingiverse.com/thing:4943077

It's licenced CC BY-NC-SA - I have granted @overange an exception as he's agreed to share his new PCB designs (which work with this shell as they have the same dimensions as Chinnery's original PCB). If you need an exception, please send me a message - of course, you're free to use this for personal use :)

I've attached a couple of little preview photos of an FDM print, I'm currently waiting on resin prints.

I have a question for all you GX4000/Plus cart fans here...
A few years ago I've ordered a bunch of GX4000 cart PCBs to make a cart for myself from time to time. So now the problem was to get a bunch of cart shells as well. I was never happy how 3D printed cases looked (from what I've seen on photos) so I've spoken to a guy who owns a machine to produce injection moulded parts and who had produced C64 cart shells previously.
He said he could produce the GX4000 shells for under 4 € a piece. Now, that was before the whole world went mad of course, so I'd need to ask him if that price is still realsitic. The problem is of course - and that's why I want to ask here - to produce the crazy expensive moulds he needs an initial order of at least 500 shells.

Now to the question: with the relatively small GX4000/Plus models userbase, is it realistic to find enough people interested in new shells to get to 500 pieces?
After that we'd finallly have the shells readily availlable to order (the guy is based in Austria / he doesn't sell quantities smaller than 10) whenever someone maybe wants to create a physical realease of his new game e.g.
So, what do you guys think? :)

Sounds interesting. 

Would 4€ (or whatever it is now) the "retail" price? Or just his cost? 

Well he's selling the C64 cart shells for 3,60 €, and the Gx4000 shells would be in the same general range (depending on how complicated the moulds are).

Those shells (and labels) are looking really great!  Nice work @Cwiiis.

I think the outlay for the injection moulded option is totally unrealistic unfortunately :(

Technically doesn't Alan Sugar own the licence to the shell designs and have the original injection moulds in his mansion's loft somewhere?  If the GX gets much more popular he won't want to give them up :P

My design costs about £3.25 per unit with delivery to print in resin from JLC3DP for an order of 20, so I'd say injection moulding is definitely not worth it at that unit cost...