Image instability with STE booster and system memory over 512k

[JezC]

@rubber_jonnie at some point can you please try this program ? https://github.com/fenarinarsa/ste_dmatest/releases/ May only work in 8MHz mode.

This on a working one. Notice the background lines are more consistent / diagonal.

@exxos - I've just run this on one of the 4meg STE's (not opened it up to check which chips are fitted just yet, maybe later today)...
I think it's showing the 'good' image - there are diagonal lines in the background which move from right to left but I wanted to be sure that is the 'good' output. Not easy to be sure on a still image...

I've not managed to wire up the sound output from the STE yet but will check for crackling audio later as well...and also dig out & test the other two (working) STEs (when I can find them)

[exxos]

I think it's showing the 'good' image - there are diagonal lines in the background which move from right to left but I wanted to be sure that is the 'good' output. Not easy to be sure on a still image...

Yeah the diagonal pattern is the good one.

It might be worth testing @ijor's blitter test program as well viewtopic.php?f=25&t=6040

I will see if I can get my STE connected up later and fiddle with the sync board to see if it shows differences in that program.. I'd assume so..

[JezC]

Ok, so I've tried the DMA Test program on two of my STE's now (both with the 1712 chip) & both exhibit a few pops on the audio as well but both have that rolling diagonal pattern on the video background

Both these appear to have the F257 & a socketed CPU so might be good test candidates for the 32MHz booster...

So, some good & some bad news with those two.

Need to find the STE with the external blitter (and an S257 IIRC) to test next.

[JezC]

Managed to find, set up and test the third STE...that shows the same diagonal background pattern...but no audible pops or crackles, just a noticeable level of high frequency noise.

I'll check on the versions of chips later, but IIRC this one has the external blitter & the S257 for the 32MHz clock, so needs that changing before I can consider the 32MHz booster.

I should mention that all 3 STEs have the 4 SIMM sockets populated, at least 2 have 4 Meg.

[DementED]

Just to close off this thread, I finally got hold of a C300588 shifter and swapped it with the C301712 that was in my STE. I wasn't holding my breath, but it actually worked! The image instability I experienced with the C301712 shifter has gone and the image is now rock solid. Result!

Anyone want a C301712 shifter?!

[Steve]

Just to close off this thread, I finally got hold of a C300588 shifter and swapped it with the C301712 that was in my STE. I wasn't holding my breath, but it actually worked! The image instability I experienced with the C301712 shifter has gone and the image is now rock solid. Result!

Anyone want a C301712 shifter?!

That's interesting! I think Exxos previously said that when he experimented swapping C301712 with C300588 it caused lots of weird issues for him, or it just didn't work. I used his buffer-board mod on my 712 shifter to fix the stability.

[DementED]

I see @Steve .

I may have spoken too soon, because with the Booster in 32MHz mode and TOS 2.06 enabled, I often get the message:
BAD ROM CRC IN CHIP E.
BAD ROM CRC IN CHIP O.

I didn't get that message with the original shifter chip, and it doesn't appear in 8MHz mode. It also doesn't appear every time I boot.

I read on another thread here that this message isn't a problem with SELTOS, but I'm not using SELTOS.

I have also noticed that I don't get sound in some games (e.g. Frontier) in 32MHz mode, but I assume that's a compatibility issue.

Anyone have any ideas?

[exxos]

I haven't got much time to read / follow all threads currently.

But it could be a problem with the 32MHz wire. You could experiment with some series resistors such as 33R,68R see if that helps.

Also, looking at this post viewtopic.php?p=107595#p107595 I assume you have P100 as 1.2K ?

Also are those black sils on the MB 4.7K ? You could try removing them..

I don't really have any other suggestions other than you have a bad connection somewhere. Maybe re-seat the booster, DUALTOS board and ROM IC and see if that solves it.

[DementED]

Thank you @exxos .

I'll try what you suggest. I really appreciate your help.