Amstrad GX4000 / Plus cartridge PCB

[dthrone]

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

[Cwiiis]

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...

[elBeton]

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

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?

It is possible to run from it CRTC3 Amstrad Plus demo ?? https://www.pouet.net/prod.php?which=72279

[VanZan]

Hi,

I just bought a GX4000 on eBay. It came with Burnin' Rubber (of course) but the cart has seen better days. Can I buy one of the cart shells somewhere or do I need a 3d printer?

[eto]

I have never seen that someone offers replacement shells. 

Can you clean this particular one? It just looks dirty. I would try that first as even the best 3D print still looks like a 3D print.

[VanZan]

That ain't dirt mate.....the shell is discolored and the sticker is faded!

Burnin' Rubber ain't particularly great so I might just toss it.

[Cwiiis]

That ain't dirt mate.....the shell is discolored and the sticker is faded!

Burnin' Rubber ain't particularly great so I might just toss it.

Don't toss it whatever you do, those carts are handy if you have a Plus and want stable behaviour with expansions... I'd gladly print you a shell, but the FDM printed shell isn't going to look as nice as a resin print and you'd probably be better off just trying to clean/treat that shell somehow. If you ever consider chucking it, send me a message and I'll take it off your hands

[luisbarna]

Hi guys



I have ordered some boards to test these cartridges (I have not found the Gerbers of the newer versions)
does anyone know the value of the capacitors? I can not find it anywhere

great job @eto

Thanks.

[overange]

This will be a 0.1 microfarad (µF) capacitor.

[overange]

This will be a 0.1 microfarad (µF) capacitor.

Forgot to mention, it needs to be a monolithic multilayer ceramic capacitor.

[eto]

This will be a 0.1 microfarad (µF) capacitor.

I think not  all of them ... let me check. I think I finally should document that PCB. 

[overange]

This will be a 0.1 microfarad (µF) capacitor.

I think not  all of them ... let me check. I think I finally should document that PCB.

I just went back over your previous posts in this topic and it does show in your design the two upper caps are 100pF and the lower are 0.1uF (100nF)

There are other carts that that use 0.1uF (100nF) in there designs.

[eto]

does anyone know the value of the capacitors

here you go. 

[eto]

it does show in your design the two upper caps are 100pF and the lower are 0.1uF (100nF)

Only one is 100pF, the other is 100nF. It's part of the ACID overdrive with the 74x112.

[luisbarna]

Thanks to both eto and overange.
The PCBs will arrive soon. When they arrive I will test and let you know.

[eto]

When they arrive I will test and let you know.

You probably don't need the upper 100NF capacitors.

Just don't put anything in there and you should be fine.

(But make sure the other one is really a 100p and not a 100n)

[luisbarna]

When they arrive I will test and let you know.

You probably don't need the upper 100NF capacitors.
Just don't put anything in there and you should be fine.
(But make sure the other one is really a 100p and not a 100n)

ok, I'll try it without that capacitor

thank you

[luisbarna]

Does it work with both EEPROM 27C1001, 27C2001, 27C4001 and EPROM 27C128, 27C256, 27C512?

[eto]

EEPROM 27C1001, 27C2001, 27C4001

yes

EPROM 27C128, 27C256, 27C512

no, they have a different footprint and wouldn't make sense anyway as it they don't have enough capacity for a cartridge ROM

[luisbarna]

EEPROM 27C1001, 27C2001, 27C4001

yes

EPROM 27C128, 27C256, 27C512

no, they have a different footprint and wouldn't make sense anyway as it they don't have enough capacity for a cartridge ROM

Understood, thanks

[luisbarna]

(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. )

Hi eto
Let me get this straight.
For using one 512kb ROM would it be like this?

And for using two 256kb ROMs would it be like this?

Thank you.

[eto]

Hi eto
Let me get this straight.
For using one 512kb ROM would it be like this?
And for using two 256kb ROMs would it be like this?

yes, all correct!

[luisbarna]

Great