C100501-001 REV.1.0

MEGA ST motherboards.
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Atarian Computing
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C100501-001 REV.1.0

Post by Atarian Computing »

From: http://www.atari-computermuseum.de/520st.htm
c100501-001-10.JPG
c100501-001-10.JPG (642.27 KiB) Viewed 5564 times
KLund1
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Re: C100501-001 REV.1.0

Post by KLund1 »

I have this board, and I think the Shifter and DMA labels are switched.
FYI
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exxos
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Re: C100501-001 REV.1.0

Post by exxos »

KLund1 wrote: Mon Aug 30, 2021 6:44 pm I have this board, and I think the Shifter and DMA labels are switched.
Yes it looks wrong.
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Re: C100501-001 REV.1.0

Post by stephen_usher »

Yeah, why would the Shifter be next to the WD1772? Makes no sense.
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PaulJ
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Re: C100501-001 REV.1.0

Post by PaulJ »

Take your ohm meter out and measure from pin 11 of the 1771 to pin 30 on the shifter and dma chip. When you get ~0 ohms that's the dma chip. The other device will have a significantly higher resistance reading.
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olivier.jan
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Re: C100501-001 REV.1.0

Post by olivier.jan »

I have the same motherboard in my Mega 2 and I keep wondering why U32 and U35 are not populated. Why bother having the sockets if these chips are not installed and why are these chips required on all other STs but not this one?
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Re: C100501-001 REV.1.0

Post by exxos »

olivier.jan wrote: Thu May 12, 2022 6:21 am I have the same motherboard in my Mega 2 and I keep wondering why U32 and U35 are not populated. Why bother having the sockets if these chips are not installed and why are these chips required on all other STs but not this one?
From factory ?! Assume someone removed them at some point ? Looks to be the 244 buffers ?
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olivier.jan
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Re: C100501-001 REV.1.0

Post by olivier.jan »

The machine still had the seal when I got it and the picture posted here shows the same sockets without the chips, so I suspect it's from Factory.
Moreover, the Mega ST 2 without this chips is still working perfectly :shock:
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Re: C100501-001 REV.1.0

Post by exxos »

olivier.jan wrote: Thu May 12, 2022 10:27 am The machine still had the seal when I got it and the picture posted here shows the same sockets without the chips, so I suspect it's from Factory.
Moreover, the Mega ST 2 without this chips is still working perfectly :shock:
:WTF:

Can you post images top and bottom of that board ?
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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olivier.jan
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Re: C100501-001 REV.1.0

Post by olivier.jan »

Ok, I should stay away from my beer pump for a while…. I opened the machine and the chips are there which makes much more sense. Sorry for the confusion. :headbang:
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