PSU related Blitter issues (Atari STE)

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Tomswork
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Re: PSU related Blitter issues (Atari STE)

Post by Tomswork » Sat Jul 25, 2020 9:32 pm

There are three traces that can be cut on 30 pin parity simms. It is these traces to the socket that can cause a short

Edit

Pin 26 28 and 29 i believe

Tom

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sascha.springer
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Re: PSU related Blitter issues (Atari STE)

Post by sascha.springer » Wed Jul 29, 2020 9:40 pm

Thanks for your comments. I have changed the RAM modules but the glitches remained visible. The inserted modules have parity chips as well but I wanted to check out another fix before cutting traces. So actually I have replaced the CPU. The old type was an MC68000FN8 and the new one reads MC68HC000FN20.

I ran the demo for more than two hours and everything seems to be fine. I‘ll do another test tomorrow but I think and hope that this has fixed the issue. 8-)

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Steve
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Re: PSU related Blitter issues (Atari STE)

Post by Steve » Wed Jul 29, 2020 10:33 pm

sascha.springer wrote:
Wed Jul 29, 2020 9:40 pm
Thanks for your comments. I have changed the RAM modules but the glitches remained visible. The inserted modules have parity chips as well but I wanted to check out another fix before cutting traces. So actually I have replaced the CPU. The old type was an MC68000FN8 and the new one reads MC68HC000FN20.

I ran the demo for more than two hours and everything seems to be fine. I‘ll do another test tomorrow but I think and hope that this has fixed the issue. 8-)
That is awesome news! Perhaps this new chip uses slightly less power or something.
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sascha.springer
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Re: PSU related Blitter issues (Atari STE)

Post by sascha.springer » Thu Jul 30, 2020 8:49 pm

Steve wrote:
Wed Jul 29, 2020 10:33 pm
That is awesome news! Perhaps this new chip uses slightly less power or something.
Thanks.

I ran two more tests lately and everything works as expected. So finally I would say that the CPU change indeed fixed my issue. :D

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sascha.springer
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Re: PSU related Blitter issues (Atari STE)

Post by sascha.springer » Sun Aug 09, 2020 11:12 am

Here's a test version of the "Fast Bobs" demo for Blitter equipped Atari STs. Please let me know if there are issues on real hardware.
Attachments
st_bobs.zip
(3.6 KiB) Downloaded 20 times

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exxos
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Re: PSU related Blitter issues (Atari STE)

Post by exxos » Sun Aug 09, 2020 11:48 am

sascha.springer wrote:
Wed Jul 29, 2020 9:40 pm
So actually I have replaced the CPU. The old type was an MC68000FN8 and the new one reads MC68HC000FN20.

I ran the demo for more than two hours and everything seems to be fine. I‘ll do another test tomorrow but I think and hope that this has fixed the issue. 8-)
Sounds like a bus loading issue again, did you try changing the pull ups ?
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tzok
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Re: PSU related Blitter issues (Atari STE)

Post by tzok » Sun Aug 09, 2020 12:36 pm

sascha.springer wrote:
Sun Aug 09, 2020 11:12 am
Here's a test version of the "Fast Bobs" demo for Blitter equipped Atari STs. Please let me know if there are issues on real hardware.
It runs fine on my BLiTTER enabled 1040STfm.

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sascha.springer
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Re: PSU related Blitter issues (Atari STE)

Post by sascha.springer » Sun Aug 09, 2020 4:03 pm

exxos wrote:
Sun Aug 09, 2020 11:48 am
Sounds like a bus loading issue again, did you try changing the pull ups ?
At first I wanted to fix the issue with "plug and play" solutions before heating up my solder iron. So actually I did not add the pull ups.
tzok wrote:
Sun Aug 09, 2020 12:36 pm
It runs fine on my BLiTTER enabled 1040STfm.
Great! Thanks for the report.

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