exxos's Atari, Amiga & retro forum

Icky wrote: 01 Jan 2019 02:12 I have a working STFM arriving in the next few days so will try the board out on that one too. If I am still having issues I will send my DVI board to exxos to check on his STFM to see if it is working there.

:thumbup:

I forgot (Again sorry) what you was using before, think it was the "ST" and STF remake ? So STFM would be good as its what I tried it out on.

exxos wrote: 01 Jan 2019 13:37

Icky wrote: 01 Jan 2019 02:12 I have a working STFM arriving in the next few days so will try the board out on that one too. If I am still having issues I will send my DVI board to exxos to check on his STFM to see if it is working there.

:thumbup:

I forgot (Again sorry) what you was using before, think it was the "ST" and STF remake ? So STFM would be good as its what I tried it out on.

Problem exists on 520ST and STF Remake so as you say trying on an STFM would be good.

Icky wrote: 01 Jan 2019 13:55

exxos wrote: 01 Jan 2019 13:37

:thumbup:

I forgot (Again sorry) what you was using before, think it was the "ST" and STF remake ? So STFM would be good as its what I tried it out on.

Problem exists on 520ST and STF Remake so as you say trying on an STFM would be good.

The plot thickens - Finally got the new (well new for me) STFM and it was functioning correctly.

Fortunately the shifter was already socketed which saved some time. I popped in the HDMI / DVI board and booted.

It did not reset. Have had it running GEMBench for over 30 minutes and still has not reset.

Just to check I put it back in the 520 ST and it starts resetting again.

One thing though is that I am getting a shimmering on the display on the STFM - will look into that next as well.

Icky wrote: 04 Jan 2019 17:44 One thing though is that I am getting a shimmering on the display on the STFM - will look into that next as well.

Thats the issue I had...

exxos wrote: 04 Jan 2019 17:46

Icky wrote: 04 Jan 2019 17:44 One thing though is that I am getting a shimmering on the display on the STFM - will look into that next as well.

Thats the issue I had...

At least we are consistent :)

So interestingly from my testing I see the following traits

ST Model	Revision	Resetting	Shimmering	Comments
520 STM	C070243 REV. E	Yes	No	Rock solid display can be seen if you can get it past resetting and playing a game
520 STFM	C070789-001 REV. C	No	Yes	Shimmering even present playing a game
STF Remake	C070789-001 REV. F	Yes	No	Revision is from the donor STFM that gave the remake most of its parts. Seems to exhibit same behaviour as 520ST

Icky wrote: 04 Jan 2019 18:07 At least we are consistent :)

So interestingly from my testing I see the following traits

Very odd..

Add this cap and I bet you be working fine...


https://www.exxosforum.co.uk/forum/viewt ... 270#p14777

Thanks for finding this out Icky! Amazing work!

exxos wrote: 04 Jan 2019 21:38

Icky wrote: 04 Jan 2019 18:07 At least we are consistent :)

So interestingly from my testing I see the following traits

Very odd..

Add this cap and I bet you be working fine...


https://www.exxosforum.co.uk/forum/viewt ... 270#p14777

Out of interest what value did you use?

Icky wrote: 05 Jan 2019 18:46

exxos wrote: 04 Jan 2019 21:38

Very odd..

Add this cap and I bet you be working fine...


https://www.exxosforum.co.uk/forum/viewt ... 270#p14777

Out of interest what value did you use?

10nF actually made the board not work - black screen.

47pF works fine.

Screen is now stable on STFM.

EDIT: Just tried the HDMI board back in the STF Remake and 520ST with the 47pF cap in place and its even more temperamental. Some times its just a blank screen like when I used the 10nF when in the STFM and not very often it might try to boot and of course reset. On reset it mostly goes back to blank. I guess the 16MHz line is not so happy in these two machines with the cap on it.

Icky wrote: 05 Jan 2019 20:06 10nF actually made the board not work - black screen.

47pF works fine.

Screen is now stable on STFM.

EDIT: Just tried the HDMI board back in the STF Remake and 520ST with the 47pF cap in place and its even more temperamental. Some times its just a blank screen like when I used the 10nF when in the STFM and not very often it might try to boot and of course reset. On reset it mostly goes back to blank. I guess the 16MHz line is not so happy in these two machines with the cap on it.

Anything over about 390pF will squash the signal to much. Its not a good fix, but I still suspect its a clocking issue.