PSU related Blitter issues (Atari STE)

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Maximilian
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Re: PSU related Blitter issues (Atari STE)

Post by Maximilian » Wed Jul 15, 2020 6:26 pm

The question is what causes the issue:
1. Lower or higher voltage
2. Ripple
3. Voltage drop
4. Something else misbehaving due to the above.

Missing something?

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

Post by sascha.springer » Thu Jul 23, 2020 9:41 am

Damn. After replacing my floppy disk drive with a Gotek device the issue is back. :shock:

I need to add that I have an IDE „backpack“ solution installed which works fine so far all the years. Probably I need another DMA hardware fix like the pull-up resistors on the bus?!

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Steve
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Re: PSU related Blitter issues (Atari STE)

Post by Steve » Thu Jul 23, 2020 11:08 am

sascha.springer wrote:
Thu Jul 23, 2020 9:41 am
Damn. After replacing my floppy disk drive with a Gotek device the issue is back. :shock:

I need to add that I have an IDE „backpack“ solution installed which works fine so far all the years. Probably I need another DMA hardware fix like the pull-up resistors on the bus?!
Hi Sasha

In your first post you mention replacing your psu with a new psu - just to clarify, what was the new psu? A completely new model or a new old stock etc? I ask because if you replaced it with an original model, the caps could still be 30 years old.

And besides that I would recommend the DMA pullup fixes & re-cap your main board.
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sascha.springer
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Re: PSU related Blitter issues (Atari STE)

Post by sascha.springer » Thu Jul 23, 2020 8:52 pm

Steve wrote:
Thu Jul 23, 2020 11:08 am
Hi Sasha

In your first post you mention replacing your psu with a new psu - just to clarify, what was the new psu? A completely new model or a new old stock etc? I ask because if you replaced it with an original model, the caps could still be 30 years old.

And besides that I would recommend the DMA pullup fixes & re-cap your main board.
The PSU has been replaced with a completely new one.

Is there an overview of the caps on the mainboard to be replaced?

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Steve
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Re: PSU related Blitter issues (Atari STE)

Post by Steve » Thu Jul 23, 2020 9:51 pm

I hope Exxos doesn't mind me posting a link to a 'competitor' but Centuriontech sells a kit, he also lists what is included:
https://centuriontech.eu/product/1040ste-recap-set/
Repairs & Servicing for Atari & Amiga machines (and any other retro computers) Located in the West Midlands UK. PM me if you require assistance.
www.solidstatesociety.co.uk

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

Post by sascha.springer » Fri Jul 24, 2020 9:13 am

Steve wrote:
Thu Jul 23, 2020 9:51 pm
I hope Exxos doesn't mind me posting a link to a 'competitor' but Centuriontech sells a kit, he also lists what is included:
https://centuriontech.eu/product/1040ste-recap-set/
Thanks. So there are more than a few to replace. :(

Today I checked when the issue appears after a cold start and with the new PSU it returns after about one hour.

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Re: PSU related Blitter issues (Atari STE)

Post by exxos » Fri Jul 24, 2020 11:16 am

Have you changed the bus pullups ?
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sascha.springer
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Re: PSU related Blitter issues (Atari STE)

Post by sascha.springer » Sat Jul 25, 2020 12:49 am

exxos wrote:
Fri Jul 24, 2020 11:16 am
Have you changed the bus pullups ?
No, not yet. I‘ll have a look on the mainboard today if there is something suspicious.

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

Post by sascha.springer » Sat Jul 25, 2020 8:33 pm

Image of the mainboard:
Image
RAMs (is the type a possible source of the issue?):
Image

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JezC
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Re: PSU related Blitter issues (Atari STE)

Post by JezC » Sat Jul 25, 2020 9:28 pm

I think @exxos has posted in a few places that the ST/STE's can be fussy when SIMMs with parity are used...and if there are only the 3 chips on each SIM then I'm pretty sure the third is for parity.

So, there's a fair chance this will be one possible issue - I think you can just de-solder the third memory device (it's usually a different part number from the other two as it's a quarter of the memory capacity) - which might be the easiest course of action if you don't have any other spare memory available.

Certainly worth ruling this out before going for more drastic potential solution IMHO

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