Another CPC back from the dead

[Munchausen]

The replacement RAM chips for my GX4000 arrived today (technically not a CPC I know). 15 minutes later and I'm playing switchblade 


It was only the RAM, not even the Z80 failed!

[CraigsBar]

Nice. Enjoy it.

[radu14m]

well done !


A stupid question: why the RAM died first ? ( in almost every case )
Is this so sensitive ?

[Munchausen]

I have no idea.. I guess it is the weakest part (Bryce?)


It's far too easy to plug the wrong voltage in to the GX4000 - it has two sockets, one for 5V the other for 11V, but it isn't marked which is which. I had to dismantle it and compare it to the schematics to figure it out!

[gerald]

It's far too easy to plug the wrong voltage in to the GX4000 - it has two sockets, one for 5V the other for 11V, but it isn't marked which is which. I had to dismantle it and compare it to the schematics to figure it out!

While the connectors are not marked (which is really bad), it is not possible to plug the original 11V power supply in the 5V socket.
The problem comes from 3rd party power supplies with their wide selection of plugs you can choose from.

[Bryce]

RAM is generally more sensitive than other ICs. Whereas the CPU and Logic chips are just a large collection of resistors and transistors, RAM ICs are huge arrays of tiny capacitors that are very sensitive to voltage spikes and depending on charge (batch) quality can deteriorate over time without any negative external influences.

Bryce.

[TFM]

Yes, spikes are the problem...