Crash with vertical grey lines

Overmann · May 5th 2020

Hi,

I've recently been experiencing crashing with my Cybervision 3D when using 320x240 8bit, hi-color and true color screens. It just comes up as a grey screen with vertical grayish and black lines (sometimes the screen is green instead of gray) and freezes the machine. Both when starting software that use those screens and in Picasso96mode when testing. Other screenmodes work fine.

I recently installed a Toccata sound card in my machine. I thought there might be some conflict but removing the card didn't help. I also tried reinstalling P96 but that didn't help either.

I have am running an A1200:
Blizzard 1260 w SCSIkit 256mb RAM

ZIV Zorro II busboard

CV3D

X-Surf 100 w Rapidroad

Toccata

FastATA ZIV

It might be a bit of a hack'y system, but it's been rock steady!

Jens · May 6th 2020

Quote from Overmann

It might be a bit of a hack'y system, but it's been rock steady!

If you have a suspicion that the Toccata has an influence, why don't you try to remove it and see if it changes the behaviour?

Further, yes, that "hacky system" deserves some extra attention, as the case and power supply will play a big role. The case should be metal (not the plastic thing that "Mikronik" used to sell), and the PSU should be a real AT-type one with P8/P9 connectors, as only these have a change of having the 5V rail as their main regulation rail. ATX PSUs with an adapter will fail. The metal case and all mounting screws will make ground contact, which is required to keep signal integrity high enough to be stable.

Overmann · May 7th 2020

I tried removing the card, but that didn't help. I have since rolled back to a backup i have of DH0 and everything is working perfectly again. Which points to it not being the toccata itself, but rather some software/library/device that people sometimes install with it. I have the Toccata and CV3D running perfectly, with AHI and P96 now, and I'll try installing SoundFX, Samplitude etc. one by one, checking 320x240 as I go along. Perhaps I'll at least figure out what breaks it. There is a thread on Amibay where people with CV3D and Toccata report the same issue, but no answers to be found.

Most (if not all) new AT-PSU's appear to be very low quality. I have a number of StarTech AT-PSU that I bought last year, but I opted to put a HQ ATX-PSU in my A1200-tower instead. Should I not have? I assumed it would be better to use a really good ATX PSU then a bad AT-PSU. And yeah, my tower is all metal, and well grounded, thankfully!

Jens · May 7th 2020

Quote from Overmann

I have since rolled back to a backup i have of DH0 and everything is working perfectly again. Which points to it not being the toccata itself, but rather some software/library/device that people sometimes install with it. I have the Toccata and CV3D running perfectly, with AHI and P96 now, and I'll try installing SoundFX, Samplitude etc. one by one, checking 320x240 as I go along. Perhaps I'll at least figure out what breaks it. There is a thread on Amibay where people with CV3D and Toccata report the same issue, but no answers to be found.

Your systematic approach will surely find the answer, and I'm most interested to learn what causes it. We may be able to fix it on the P96 side, even if it's just with a warning that a certain piece of software causes problems.

Quote from Overmann

Most (if not all) new AT-PSU's appear to be very low quality.

I did a quick search and found that new AT PSUs are actually offered. What a surprise! I would have expected them to be phased out long ago. With all the cost-reduction going on, I do share your fear that they are low-quality, but don't dare to express it as an opinion until I actually measured them. After all, these cheap Chinese products are not there because they can't do any better - they are there because western buyers are pushing prices down without looking at quality (or accepting lower quality - doesn't matter how you twist it).

You can also go the other way in Asia; if the buyer makes clear that quality, not price is the prime goal, you can get very good products from all-Asian components. However, quality comes with a price tag, no matter where on the planet you produce.

Quote from Overmann

I have a number of StarTech AT-PSU that I bought last year, but I opted to put a HQ ATX-PSU in my A1200-tower instead. Should I not have?

That depends on the main regulation rail of these PSUs. You have to know that most ATX power supplies have 12V as their main regulation rail, and 5V does not get the "prime attention" that it got when AT PCs were state-of-the-art. The 5V rail is merely "co-regulated" and floats heavily with load on 12V on ATX PSUs. For the Amiga, which uses 95% of it's power on the 5V rail, you should have proper regulation on 5V, without dependency on the 12V load.

If you have a PSU's output power rating, you can make an educated guess about the main regulation rail by calculating the output power (multiply voltage by max. amperage to get Watts): The rail with the highest output power is likely to be the main regulation rail, and the other output voltages are floating with load on the main regulation rail.

Now that you've found that you have a software, and not a hardware issue, these calculations are mostly of academic nature. Still interesting, though.