exxos's Atari, Amiga & retro forum

progress looking good folks :)

dave

exxos wrote: 30 Sep 2018 22:23

Forgottenmyname wrote: 30 Sep 2018 22:06 I think the sound should be ok as is.

:thumbup: Its the same circuit as the STFM pretty much anyway...

One thing is can you guys check a GEM window... I always had noise floating left to right like on this image...

I don't see any of those lines on the STF board as you can see but I do get this fuzziness (bottom of the file icons) moving up the screen

I cant try on an STFM at the moment as my workspace has been trashed trying to test on different monitors.

Icky wrote: 30 Sep 2018 22:35 I don't see any of those lines on the STF board as you can see but I do get this fuzziness (bottom of the file icons) moving up the screen

That is really good for the drag bar then...Hopefully will show the same on my LCD (Falcon shows just fine btw)

No idea where the other noise comes from though.. might need more gnd connections on your cable, or shielding...

One thing I never thought about...

There are some 470pF caps across the video port... If its not the cable, then it could just need some filtering..

Though I did experiment with caps while tracing noise faults last year.. higher value caps "blur" the image but do reduce noise.. not a good fix... but shielding on the cable and using it as gnd I would assume fix the problem anyway.


EDIT:

Its also possible the RGB drivers could be picking up noise from the master clocks.. really the RGB section should be enclosed in a metal can.. but was hoping it wouldn't come to that... Its also possible some noise might be generated internally on the shifter.. We should be able to clamp it with some low pF caps if needs be anyway...

exxos wrote: 30 Sep 2018 23:06 Its also possible the RGB drivers could be picking up noise from the master clocks.. really the RGB section should be enclosed in a metal can.. but was hoping it wouldn't come to that... Its also possible some noise might be generated internally on the shifter.. We should be able to clamp it with some low pF caps if needs be anyway...

Ok. I’ll start with making sure there is good shielding and gnd. I’m hoping to get this cable in shape that the flicker goes away.

So, some good progress for today.

Got the keyboard fixed and my floppy drive working properly now.

The problem was with the keyboard and a poor connection on one of the ACIAs.

So far though, I can only get a gotek or stfm floppy working, the Exxos 1.44 and Mega ST drives don't want to play.

I ran the Gembench test and got the same initial results of 99% that Icky did. Will try the 32.4285mhz crystal I have once I've made up the adaptor board tomorrow.

Forgottenmyname wrote: 06 Oct 2018 16:51 So far though, I can only get a gotek or stfm floppy working, the Exxos 1.44 and Mega ST drives don't want to play.

Did you add the pull ups on the 1772 inverters ?

Yes I did that.

Not too worried for now as stfm and gotek work.

Forgottenmyname wrote: 06 Oct 2018 16:51 So, some good progress for today.

Got the keyboard fixed and my floppy drive working properly now.

The problem was with the keyboard and a poor connection on one of the ACIAs.

So far though, I can only get a gotek or stfm floppy working, the Exxos 1.44 and Mega ST drives don't want to play.

I ran the Gembench test and got the same initial results of 99% that Icky did. Will try the 32.4285mhz crystal I have once I've made up the adaptor board tomorrow.

Great news :)

My keyboard issues have gone away too on cleaning up the ACIAs area (new DILs) and better keyboard pin 8 patch instead on the extension cable I was using.

Sounds like our boards are almost identical. My next job is around the floppy connector now I have my monitor un-f*ck board sorted.

I haven't tested the parallel as I don't have a cable or suitable printer.

Icky wrote: 06 Oct 2018 18:38I haven't tested the parallel as I don't have a cable or suitable printer.

An obvious test case would be PARCP-USB, if you know someone around with that device. If not, it's an useful thing to buy anyway. ;-)