Schematics or ram circuit info for Tecfri sauro or tricky doc

[myPinballs]

Hi,

Looking for any info on the main ram circuit for this era of board. Is battery backed ram, but i cannot fathom out the !CS activation for the ram currently.

Any schematics available anywhere or someone have some info on this. My !CS line is dead (open, not high or low), but i cannot understand the circuit. Doesn't seem to be fed from anything cpu related. Just seems to be from some pnp transistor & res/cap situation and the backup battery.

Or if someone had a board that they could test what the circuit does at power up that would also be useful

 

[Georgian2]

Hi,

Looking for any info on the main ram circuit for this era of board. Is battery backed ram, but i cannot fathom out the !CS activation for the ram currently.

Any schematics available anywhere or someone have some info on this. My !CS line is dead (open, not high or low), but i cannot understand the circuit. Doesn't seem to be fed from anything cpu related. Just seems to be from some pnp transistor & res/cap situation and the backup battery.

Or if someone had a board that they could test what the circuit does at power up that would also be useful

Write protect when the ram is powered from the battery. I don't have a board.

 

[Georgian2]

Did you sort it out? I have an Sauro on my bench now. Need to make an adapter for it and I can make some tests for you.

 

[myPinballs]

I got passed the ram issue with roms and ram ok. but the screen was still messed up up graphics wise with the text and it didnt progress to the techfi logo part of the boot, or it crashed at that point. Thats were i got stumped with no schematics. Also theres loads and loads of pal ics with no clue what they do to!

 

[Georgian2]

Could you please tell me the value of the sound potentiometer? Mine has an 2K in and very noisy.