exxos's Atari, Amiga & retro forum

Good news part 1, hopefully followed close by part 2,

The STF boots to desktop. I've still not fixed the Vsync, which is next, the screen just keeps rolling but i can see text etc.

Also the screen is very dark, so not sure I've implemented the DAC board properly.
I didn't fit the RGB part of the board but have fitted the monitor unf*ck board.
I have three 39 ohm resistors in the line to the RGB, so guess I could try removing them?

Next step to get that Vsync working now.

Yeah you can try removing the resistors.. The jumper on the DAC board can also down/up the brightness a tiny bit as well.

EDIT:

If you have the diodes in place from the original RGB circuit then that drops the brightness a lot.

exxos wrote: ↑Mon Dec 24, 2018 8:27 pm

Yeah you can try removing the resistors.. The jumper on the DAC board can also down/up the brightness a tiny bit as well.

EDIT:

If you have the diodes in place from the original RGB circuit then that drops the brightness a lot.

Only fitted the diodes to the composite circuit on the STF. what about the large caps on the DAC?

Found vsync goes to the MMu but doesn't make it to the monitor port, odd but at least I know what the problem is.

Forgottenmyname wrote: ↑Mon Dec 24, 2018 8:34 pm what about the large caps on the DAC?

It looks like they are not needed. I removed them on the V3 layout in fact.

Forgottenmyname wrote: ↑Mon Dec 24, 2018 8:34 pm Found vsync goes to the MMu but doesn't make it to the monitor port, odd but at least I know what the problem is.

Ah yep, think you mentioned that the other day..

ahh I was thinking H-sync before with the fixes...

https://www.exxosforum.co.uk/forum/viewt ... 1185#p9963

VSYNC goes from the MMU to GLUE to RGB socket and the 3 diodes in the comp-gen circuit...

yeah, it confused me a little, LOL.

Vsync is fixed but still very dark pic, so wondering if I've cocked something up on the DAC board

Exxos, where did you pick up BLANK from? I think its something to do with that. I've tried it on Glue pin 36 but doesn't make any difference to the darkness of the display.

Forgottenmyname wrote: ↑Mon Dec 24, 2018 9:43 pm Exxos, where did you pick up BLANK from? I think its something to do with that. I've tried it on Glue pin 36 but doesn't make any difference to the darkness of the display.

Can pick it up from the yellow traces...


The dark stuff started around here...

https://www.exxosforum.co.uk/forum/viewt ... 230#p14730

Thanks will have a read later when everyone else is having their post dinner sleep.

Have you made any progress yet

exxos wrote: ↑Tue Jan 01, 2019 4:14 pm Have you made any progress yet

Christmas and other stuff got in the way. I think I'll pop the original RGB bits on the board and get it all working ok with that and then sort out the DAC.