Uh... Make that Hz, not MHz. Oops my mistake!
Here is a written description.Dwight Thanks a lot! I think I understand that part now. And thanks also for the role of Schmitt-trigger inputs, you anticipated my question about them :)

Let me try to sum things up concerning timings with the program ...

It is so simple it makes me feel dumb now! Learning something new everyday :) I'm sorry if my questions or remarks sound silly, but as I explained earlier I am no specialist, merely a science teacher with some academic knowledge of electronics, but no experience of complete systems.

So if I ...

U4B section A (pins 1, 2, and 3) time the power-up reset to somewhere in the 70ms area. The actual length depends on not just resistor (component 10) and capacitor (component 11) tolerances, but on the size of the hysteresis size of the Schmitt-trigger gate input and how fast the power supply comes ...

Hello all,

Now I've been able to move a little further with my understanding of the Synthex. There is a particular piece of schematics I am currently stuck on :
Image no longer available: https://s3.postimg.org/wkonadtvn/Rest-_Reset.png
REST is an output of an LS138, RESET is pin 40 of the 6502 ...

Thanks Jeff!

Now I see (at least one reason) why my attempt to de-assemble some ROM files did not make any sense; I'll have to translate them first

Hi there,

I am a big fan of JMJ and love the sound of the synthex.

I do not own one (it is quite a budget these days...) However, I recently decided to dive into its electronic diagrams to understand how it works. Concerning the 6502, I found something that looked strange to me (I have some ...