Another doubt, the first burn of the EPROM has to be made ​​on one of the SRAM sockets changing the WE pin, with the older EPROM  still installed, because at first the 29X040 is empty and we haven't yet ExDOS in it, no?


Seems like a vicious circle...


------------


Otra duda, la primera programación de la EPROM ha de ser realizada en uno de los zócalos de las SRAM cambiando el pin WE, con la vieja EPROM aun instalada, porque al principio la 29X040 está vacía y aun no tenemos EXDOS en ella, no?


Parece un circulo vicioso...

And about the SRAM. which is the better?

Type not important, just we need a DIP32 package, these what I found in DIP:
Alliance Semiconductorts AS6C4008
Samsung K6X4008C, KM684000
Hitachi HM628512

The only old EXDOS EPROM I have is of 128k, and to put it on a cartridge I need another more lesson, as that bay lacks a memory direction line(if I`ve understood you correctly).

May be inserting EXDOS as an extension by tape can do the trick... I  have plenty of RAM.

How can I extract the content and do an EXDOS EXOS extension?

A local electronics store here in Madrid have the chips:

Each AS6C4008 costs 3,99 Euro, and the AM29F040 2,66 Euro.

I am able to do those welds, but the process of programming is what intimidates me.

To do the things more rapid (and probably safer...), how about if I send you the EPROM and you fill it of whatever you think necessary....?

In the meanwhile I can adapt the EXDOS card sockets.

Then, once with the EPROM returned, I'll only have to switch chips.

And that way the EP may be operative while waiting.

------------------

Yo soy capaz de hacer esas soldaduras, pero lo que me intimida es el proceso de programación.

Para hacer las cosas mas rápidas (y probablemente mas seguras...), ¿qué tal si te envío la EPROM y tú la llenas de lo que te parezca necesario...?

Mientras tanto yo puedo ir adaptando los zócalos de la tarjeta EXDOS.

Entonces, una vez la EPROM de vuelta, solo tendré que intercambiar los chips.

Y de ese modo el EP seguirá operativo durante la espera.

To do the things more rapid (and probably safer...),

The fastest way the "current EPROM to the cartride" and flash the new ROM.

how about if I send you the EPROM and you fill it of whatever you think necessary....?

Yes it is possible, but I think better if you buy the IC from me, then no two shipping cost just one!

If I have not opened before the EP was for not to break the membrane keyboard. But I bought a membrane just in case, so I can open it and change the internal ROM. Also I want to install a switch to the speaker.



I have not purchased yet the components, thinking you will "graciously" offer yourself. Thank you very much, we will do that. You purchase, program and send it to me. And the internal EXOS ROM too if you want. Think it must be upgradeable "in situ" too as I've not the programming machine.



I don't know how I'm going to thank you it enough....


--------------------------



Si no he abierto antes el EP ha sido por no romper la membrana del teclado. Pero he comprado una membrana por si acaso, así que puedo abrirlo y cambiar la ROM interior. También quiero instalar un interruptor al altavoz.

Aun no he comprado los componentes, pensando que tú te ofrecerías "cortésmente". Muchas gracias, así lo haremos. Tú lo compras, lo grabas y me lo mandas. Y el EXOS ROM también si quieres. Piensa que también tiene que poder actualizarse "in situ", pues yo no tengo maquina de programar.

No se como voy a agradecértelo suficientemente.