Graphics corruption

[Karlos]

What software versions are you using? Specifically RTG and so forth?

But I read somewhere about a certain issue with sound output, when you only power the motherboard via the floppy connector?

Never run your system from the floppy power supply only, especially if you have a BlizzardPPC + BVision.

My 1200T has the same hardware and is very stable. Power is supplied from a single 150W PSU via the original power connector (0, 5, 12 and -12V) with supplemental power for the 0, 5 and 12V rails via the floppy port. This ensures that you aren't pushing all the current drawn by the motherboard/accelerator/graphics card through one location.

You need to supply power for the -12V line for proper operation of audio and serial, unless you like your audio half wave rectified and your RS232 incapable of a full voltage swing for signal low

[Karlos]

Im running the latest CGX4 with the very latest patches. I believe version number is then 4.3 rc5. Im using a tweaked bvisionppc 'monitor', that goes up to 76khz -is that a problem? I remember tweaking that monitor a little while before the trouble started.

Anything is possible. Revert it and see what happens.

I'd start by stripping down the system to just the absolute minimum you need for RTG: your accelerator card, graphics card and work your way back up.

[Karlos]

Overclocking the video memory bus or the video chip can also cause problems like these. Can't you just try with a lower res?

I am inclined to agree that it's a configuration (or power or both) issue simply because the chance that 3 successive bvision cards all suffer the same specific defect seems remote.

Make sure any overclocking tooltypes are disabled in the monitor driver (hint: 2AIDEMREPYMNONAFADELLATSNII, MELTDOWN)

[Karlos]

good one! they were enabled indeed, but disabling them didnt help at all.

Try a completely clean reinstall of cybergraphics, removing any monitor spec files that were created. I'm not entirely convinced your problem is with a 76kHz monitor preset (IIRC, I have a 96kHz one, but it's all in the pixel clock), but there are many parts to a typical CGX install and any one of them could be duff.

Once reinstalled, try a completely bog standard VGA 640x480 mode, and see if you get any corruption. Then work your way back up, but ensure that when defining your monitor spec your pixel clock does not go outside the acceptable range for your RAMDAC*. For 8/15/16 bit depths, this is something like 230MHz, down to 145MHz for 24 bit (packed pixels - not 32-bit with ignored alpha) and around 100MHz for 32-bit.

It has been a long time since I used it, but I recall the CGX the tool that configures your display modes won't allow you to define modes that will stray outside the pixel clock limits, but IIRC, you tell it what those limits are.

*cue Delshay and his fastest RAMDAC in the west. Whatever you do, don't listen to him, he's modified his hardware. Stay inside the limits.

[Karlos]

Just think, for the amount of money you paid for that setup, you could have gotten yourself an AmigaOne with OS 4.1 and had hundreds of dollars left over. You people with your Amiga 1200 computers really crack me up, lol.

Have you ever actually been an Amiga enthusiast, or are you just another Johnny-come-lately fanboy?

My advice:  Part that piece of crap out and sell the items on eBay.  Then take about $1000 of the money you will get and buy yourself an AmigaOne with OS 4.1, and an ATI Radeon graphics board.  You will have a much nicer Amiga computer, for less money.

Speaking as someone that owns both, that "piece of crap" as you so politely put it is running 20 years after production. I really doubt many of Eyetech's systems will be.


@rvo nl

If a clean reinstall of CGX doesn't work, you might consider a physical strip and rebuild, cleaning all the connectors thoroughly of any grime and dust.

Also, perhaps some other peripheral is interfering with your system. Rebuilding it a component at a time should help eliminate that.

[Karlos]

Suddenly I had sound output again! Probably a problem with the -12v line?

Without a working -12V rail, sound and serial will both have problems for starters. You may get no sound at all, or horribly clipped sound (caused by rectification of the negative half of the waveform). Serial may exhibit all sorts of weird problems or just flat out refuse to work, depending on what is attached. The electrical specification for RS232 considers logic low to be anything from above +3V (up to around +25V) relative to ground and logic low to be anything below -3V (down to around -25V) respectively. IIRC, the amiga serial port uses +12V and -12V respectively for these.

[Karlos]

Don't think there's any connector involved here, the distortion wouldn't be so static

We don't know from a screenshot how the distortion develops over time to know if it is static or not. It never hurts to clean out dust and crap anyway, in my experience.

@rvo_nl

You might have some dust or dirt in the MiniPCI connector where the BVision attaches. Make sure you clean it out during reassembly.

If it was a more general memory corruption issue on the PPC board, I'd expect your machine to lock up pretty quickly as it would surely overwrite something important soon enough.

[Karlos]

Well, a quick WHOIS confirms it is indeed Doomy (Hans Campbell). What is the 2012 Amiga.Org position with him ?

Until I am told otherwise by the admin, doomy is banned indefinitely. Some further checks will be necessary however.

-edit-

Checked and unsurprisingly, a big overlap with previously banned Doomy sockpuppets.

[Karlos]

Do those corrupt vertical lines stay at the same position on the screen when you move the Edit Mode window, or do they stay at the same position *in* the Edit Mode window if you move it?

If they are fixed relative to the screen itself, this suggests a possible DAC problem or issues with the pixel clock for that screenmode.

If they get blitted around with the rest of the window, then something is definitely corrupting the Video RAM.

[Karlos]

they are fixed relative to the screen. they are always in the same position. even when I change the pixel clock for the mode myself. youre talking about the DAC, that is part of the bvision, right? how can it be that they all have the same issue? doesnt make sense.. interference? ..the kind that only appears in 16 bit modes? Im lost..

Yeah, it does seem strange, to be honest.

Can you tell us exactly which versions of all the CGX components you have?

Perhaps I can compare them with my CGX 4.2 install which I know is working just fine.

[Karlos]

Fixed artifacts in certain modes = graphics board problems, an electrical problem if you will. Then of course one has to rule out confounding hardware issues such as a monitor "near out of sync" or similar. Think, "it doesn't move," so not software.

Since all the memory and pixel clocks on the Permedia2 are programmable, such issues can still be down to software and the improper configuration thereof.

[Karlos]

Uh, the fact the the hardware is programmable does not make it a software problem any more so than a resistor can be "programmed" by varying the voltage applied. "Firmware" is software imbedded in hardware but it, like "software" runs on hardware. The software/firmware will not alter the properties of the transistors themselves.

I think you misunderstood me. *If* the corruption is caused by an "almost out of sync" type problem, it could be symptomatic of a misconfigured clock. Trust me, I've poked around in those registers myself and gotten into trouble for it.

Three separate cards with the same, specific hardware defect seems a bit of a stretch.

[Karlos]

If done correctly overclocking has nothing to do with this problem. I have finished the Ultra Bvision which is clocked 125Mhz and sets a new world record.

Umkay, this helps the OP solve his display problem how, exactly?

[Karlos]

thanks.. I guess

Ofcourse I have the latest flash.

If your card really is damaged, it's possible it can be repaired. There used to be an amiga repair centre (based in France, I think), though I don't know if it is still going.

Failing that, you have a few "BlizzardWizards" here, such as Statchu or Delshay, though whether or not they would want to repair it or just buy it from you in order to refurbish it and sell it on, I couldn't say.

[Karlos]

The SGRAM chips are the ones just visible at the bottom of your screenshot. There should be 8 of them in total, 4 on each side of the card.