Atari STE Blitter objects demo (new record)

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dml
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Re: Atari STE Blitter objects demo (new record)

Post by dml »

Yeah, either temperature alone or perhaps temperature combined with a socketed chip? Or a dry capacitor on the board.

Anyway I did a bit of extra science for you - see below. It appears I have an STE with integrated blitter - the blitter socket is missing.

The CPU and ram get quite warm :)
Last edited by dml on Fri Jul 24, 2020 7:56 pm, edited 1 time in total.
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Re: Atari STE Blitter objects demo (new record)

Post by dml »

(Not sure if this will survive intact and readable with the JPG compression but there is a size limit for file attachments).
board2.jpg
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Re: Atari STE Blitter objects demo (new record)

Post by Frank B »

Sascha if it's the standalone blitter chip that's gone bad I have a spare one somewhere.
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Re: Atari STE Blitter objects demo (new record)

Post by masteries »

dml wrote: Fri Jul 24, 2020 12:47 pm Yeah, either temperature alone or perhaps temperature combined with a socketed chip? Or a dry capacitor on the board.

Anyway I did a bit of extra science for you - see below. It appears I have an STE with integrated blitter - the blitter socket is missing.

The CPU and ram get quite warm :)

img_thermal_1595594516013.jpg
img_thermal_1595594505612.jpg
A thermal camera... an impressive toy you have!

An STE without discrete blitter, that supports blitter operation and usage... interesting... first notice I have of relocation of this ASIC,
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Re: Atari STE Blitter objects demo (new record)

Post by dml »

masteries wrote: Fri Jul 24, 2020 5:31 pm A thermal camera... an impressive toy you have!
:) it comes in useful for fixing roofing and broken electronics in equal measure.
masteries wrote: Fri Jul 24, 2020 5:31 pm An STE without discrete blitter, that supports blitter operation and usage... interesting... first notice I have of relocation of this ASIC,
I'm not sure when that change was made - but the '89 date on this board puts it quite early. I'm actually a bit disappointed as I was hoping to find a real blitter there!
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Re: Atari STE Blitter objects demo (new record)

Post by Anima »

dml wrote: Fri Jul 24, 2020 12:47 pm The CPU and ram get quite warm :)
Nice images! I will have look tomorrow or probably this night. :D
I just want to have a working machine badly! ;)
Frank B wrote: Fri Jul 24, 2020 5:14 pm Sascha if it's the standalone blitter chip that's gone bad I have a spare one somewhere.
Thanks for the offer! :)
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Re: Atari STE Blitter objects demo (new record)

Post by alexh »

The Combo GST MCU with number C302183-002/B has the integrated blitter, all photos are dated 1991 that I can find. The GST MCU without a blotter was C300589-001. They are interchangeable with only a few minor mods
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Re: Atari STE Blitter objects demo (new record)

Post by dml »

So you have a socketed blitter.

What is the board mounted over the CPU?
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Re: Atari STE Blitter objects demo (new record)

Post by Anima »

dml wrote: Sat Jul 25, 2020 6:17 pm So you have a socketed blitter.

What is the board mounted over the CPU?
It's an IDE interface piggybacked on the CPU. It's not the best solution due to the plugging but it works.
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Re: Atari STE Blitter objects demo (new record)

Post by Anima »

The demo runs now. Will have a look in about one hour how hot the chips are...
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Re: Atari STE Blitter objects demo (new record)

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Anima wrote: Sat Jul 25, 2020 6:26 pm The demo runs now. Will have a look in about one hour how hot the chips are...
More than one hour has passed. No signs of glitches yet. :shrug:

Edit: Blitter has room temperature...
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Re: Atari STE Blitter objects demo (new record)

Post by Anima »

Until now only a few almost not noticeable glitches occurred (with all shieldings removed). I also removed the piggyback IDE controller so probably the CPU gets too hot with the IDE PCB sitting above it?!
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Re: Atari STE Blitter objects demo (new record)

Post by dml »

Yes it could be the piggyback expansion. It's sitting on a mechanical contact between the 68k and bus grant logic.

And I doubt it was tested against 23 blitter bobs at 50hz for 3 hours :-p
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Re: Atari STE Blitter objects demo (new record)

Post by Anima »

dml wrote: Sat Jul 25, 2020 8:09 pm Yes it could be the piggyback expansion. It's sitting on a mechanical contact between the 68k and bus grant logic.

And I doubt it was tested against 23 blitter bobs at 50hz for 3 hours :-p
:lol:

It seems that even without the IDE interface PCB the issues are getting worse in a closed case. :cry:

I'll check the RAM tomorrow. It seems that they have a parity chips which could also lead to problems.

https://www.youtube.com/watch?v=kw9j3Gm ... e=youtu.be

Update: even more glitches some minutes after the video recording... :(
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Re: Atari STE Blitter objects demo (new record)

Post by dml »

So its related to temperature, but nothing is particularly hot?

This might be a bad idea - but what happens if you lightly press the chips (e.g blitter) with a finger while its running? you'd need to run with the shield off and the keyboard set aside to try it.
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Re: Atari STE Blitter objects demo (new record)

Post by EvilFranky »

Anima, I think you may have just inadvertently created the first ever Atari ST blitter stability testing tool!

Hope you manage to get it sorted :)
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Re: Atari STE Blitter objects demo (new record)

Post by Anima »

dml wrote: Sat Jul 25, 2020 9:48 pm So its related to temperature, but nothing is particularly hot?

This might be a bad idea - but what happens if you lightly press the chips (e.g blitter) with a finger while its running? you'd need to run with the shield off and the keyboard set aside to try it.
The CPU gets warm but not really hot. At least as far as I can tell from touching the top surface. The RAM SIMMs are also getting warm. I suspect that the CPU is the culprit. I will try to cover the CPU to keep it warm and try to press the package a bit when the glitches are fully visible. :coffe:
EvilFranky wrote: Sun Jul 26, 2020 12:09 am Anima, I think you may have just inadvertently created the first ever Atari ST blitter stability testing tool!

Hope you manage to get it sorted :)
Thanks, it‘s really getting annoying. I wonder who else has the same problem.
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Re: Atari STE Blitter objects demo (new record)

Post by tzok »

I have noticed, that one of the balls is moving noticeably slower and more "shaky" than all the rest.

On my STe (early production unit) demo runs fine, work field graphics seem to be fine, although some glitches happen on the bottom border (yet this may be caused by my upscaler). This is almost stock STe, but with CPU replaced to MC68HC000P16, and 4 MB RAM. I was wondering if it would run on Blitter equipped ST, but unfortunately I have only 1 MB in my STfm.
Last edited by tzok on Sun Jul 26, 2020 4:00 pm, edited 2 times in total.
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Re: Atari STE Blitter objects demo (new record)

Post by Frank B »

I had an STe which behaved unreliably with a momsterbaord fitted. It turns out Atari put a 6 mhz 68000 in it. it was fine with being overlocked to 8 until the monster board went in. Simbo replaced it with a 12 mhz part and the machine was rock solid.
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Re: Atari STE Blitter objects demo (new record)

Post by Anima »

tzok wrote: Sun Jul 26, 2020 11:04 am On my STe (early production unit) demo runs fine, work field graphics seem to be fine, although some glitches happen on the bottom border (yet this may be caused by my upscaler). This is almost stock STe, but with CPU replaced to MC68HC000P16, and 4 MB RAM. I was wondering if it would run on Blitter equipped ST, but unfortunately I have only 1 MB in my STfm.
Thanks for the report.

Please note that the demo does not work on Atari STs with a Blitter yet. I will prepare a version ASAP. ;)

Why did you replace the CPU? Was there a special reason for it?
Frank B wrote: Sun Jul 26, 2020 12:31 pm I had an STe which behaved unreliably with a momsterbaord fitted. It turns out Atari put a 6 mhz 68000 in it. it was fine with being overlocked to 8 until the monster board went in. Simbo replaced it with a 12 mhz part and the machine was rock solid.
Wow, that's quite a crazy story. So you identified it by the CPU markings? AFAIK there's no MC68000 PLCC version with 6 MHz!?

My STE CPU reads as follows:
Image

I am actually testing now with the CPU covered to provoke a higher CPU operating temperature but even after 15 minutes no glitches appear.
Image

Next I'll cover the RAM SIMMs. I am slowly getting clueless about the reason for this issue. :cry:
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Re: Atari STE Blitter objects demo (new record)

Post by dml »

I'd now be tempted to pop the ICs out of the sockets, rub the pins with something lightly abrasive, wash with alcohol and put them back in.

But with these it's best done with a special IC pulling tool (can find them cheap on ebay). Or a great deal of care.
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Re: Atari STE Blitter objects demo (new record)

Post by Frank B »

I think so. It wasn't rated for 8 and ran too hot. There's a part number here for a 6 mhz model https://archive.org/stream/bitsavers_hi ... k_djvu.txt
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Re: Atari STE Blitter objects demo (new record)

Post by tzok »

Anima wrote: Sun Jul 26, 2020 4:26 pmWhy did you replace the CPU? Was there a special reason for it?
It was supposed to fix the "bad DMA" problem, and actually it did. It also produces much less heat.
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Re: Atari STE Blitter objects demo (new record)

Post by Anima »

dml wrote: Sun Jul 26, 2020 4:53 pm I'd now be tempted to pop the ICs out of the sockets, rub the pins with something lightly abrasive, wash with alcohol and put them back in.

But with these it's best done with a special IC pulling tool (can find them cheap on ebay). Or a great deal of care.
You know what? I ordered one on Ebay yesterday along with a new 20 MHz CPU. :lol:

But while I am waiting for it I changed the RAM SIMMs, reattached the IDE controller and put everything together again. Same result: glitches after a few minutes.

Well, I will wait for the new CPU and think about another strategy to find a fix for that damn problem. :evil:
tzok wrote: Sun Jul 26, 2020 5:15 pm It was supposed to fix the "bad DMA" problem, and actually it did. It also produces much less heat.
Good point. Glad it solved your problem. I ordered a new CPU as well (20 MHz) for a replacement. Just for keeping it cooler but also hoping for a lucky punch to get rid of that nasty issue.
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