video corruption

[koshman]

Hi,
I have a problem with my A1200 + Blizzard 1230 MKIV 64MB. I'm trying to run the demo Pulse and while it does run the picture is corrupted - the initial Nerve Axis title doesn't draw as it should and some following effects - mostly writing, 2D stuff are corrupted, too. I have problems running other demos (freezing and such), but that might be caused by million other things. When I run games (usually older OCS ones, not very taxing on the HW) I don't have any problems. Also WB seems to work fine. I've tried different memory modules and the problem persists. I also just bought B1260 and it acts the same with it.

This is an A1200 I bought refurbished from Amigakit with the stock PSU - very small and light one, 2B revision mobo, Escom. Now the PSU might cause some issues like freezing sure, but graphical corruption (btw, the artifacts are always totally identical, not random)? Plus there is only a CF drive in the Amiga apart from the turboboard and even the stock PSU should be able to power that (according to specifications anyway).

I'm going to buy the 4.5A A500 PSU to rule out that possibility, but do you think the mobo might be faulty? Btw, I tried both RGB and composite out with the same results.

[koshman]

I understand it may sound a little ridiculous basing my suspicion of a bad mobo on just one demo, so could you advise me on how to best test the A1200?
Thanks.

[Franko]

Hi Koshman,

If it's only the one demo that your getting corrupt gfx on and if everything else is running fine without corrupt gfx, then it's most likely to be the demo and not your amiga.

Probably it's an old demo (ie: not written for the A1200), try running a degrader like TUDE first and see if that solves the problem.

[ferrellsl]

I think Franko is correct.  I suspect that the demos don't like your Blizzard and/or your A1200 chip set.  The demos were most likely written for stock A1000/A500/A200 Amigas.  You could also try running your demos by first holding down both mouse buttons at boot time.  Then select an ECS or OCS boot.

[zipper]

Probably it's an old demo (ie: not written for the A1200), try running a degrader like TUDE first and see if that solves the problem.

Nope. What I know it's an AGA demo for 030+.

[koshman]

Yes, Zipper is right, this demo was made for expanded Amigas. I've run it on A1200/030, A4000/040, A4000/060 and WinUAE and never had a problem. The current machine is at least SW-wise still WIP so I haven't tested many other demos/games. But I'm currently working on it...

EDIT: Hmm, Lapsuus plays great and that's heavier than Pulse. I thought that maybe I have problems with corrupted data on the CF card, but when I try and run the Pulse from it under UAE, it works flawlessly.

[zipper]

Yes, downloaded it just from Aminet and ran via Amiga Forever on my laptop - no problems on the screen, it ran fine with default settings.

[koshman]

Hm, I get consistent graphical corruption in specific places - 2D graphics like the Nerve Axis writing at the beginning of the Pulse demo, faces of characters in RPG games - EOB, Bloodwych, DMII etc. This has probably nothing to do with the PSU, which I suspected earlier. Is it possible that this is caused by data/filesystem corruption? Everything is on a CF card prepared in WinUAE (maybe a problem with maxtransfer or something?).
Besides this the system does all kinds of nasty things, but they can't be clearly linked with the graphical corruption issue.

[Franko]

Hm, I get consistent graphical corruption in specific places - 2D graphics like the Nerve Axis writing at the beginning of the Pulse demo, faces of characters in RPG games - EOB, Bloodwych, DMII etc. This has probably nothing to do with the PSU, which I suspected earlier. Is it possible that this is caused by data/filesystem corruption? Everything is on a CF card prepared in WinUAE (maybe a problem with maxtransfer or something?).
Besides this the system does all kinds of nasty things, but they can't be clearly linked with the graphical corruption issue.

Simplest thing to do is remove all boards/expansions etc.. and run the computer for a while to see what happens, adding back in one at time each peripheral until the problems occur.

It may sound like a long and boring process but it's the best way to figure out the problem. Of course, having said that and the bare machine shows up the problems then it could well be the motherboard or the PSU.

[kolla]

Silly question perhaps, but one never knows... you have tried starting the demo from first CLI, that is, booting without startup-sequence?

[koshman]

Yeah, I guess that's what I'll do. Thanks.
And also try a mechanical HDD in place of the CF card...

EDIT: @ kolla: Yes, I have. Also under vanilla OS3.1, ClassicWB and OS3.9. Still the same symptoms...

[koshman]

I got it! It was the CF card - either I did something wrong when I was installing PFS3 or set a bad maxtransfer value. I formatted all partitions in FFS (just to be sure) and set maxtransfer to 0x1fe00 and everything works great - no problems with demos and all of the other problems I had (WHDLoad games and some apps) are gone too.
Now I can finally put my B1260 through its paces :evil: :angryfire: :pissed: :laugh1:

 EDIT: I just watched Pulse again, I love this demo. I'm so happy! I love Amiga!

[Franko]

Glad you got things sorted Koshman, now you can put your miggy to good use...