[PICS] Exxos 4 Meg RAM card - STM edition

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spiny
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[PICS] Exxos 4 Meg RAM card - STM edition

Post by spiny »

Link to bigger pics here: http://www.spiny.org/atari/photos/exxos_4meg_stm/

another [PICS] thread, this time a 4Meg RAM card from Exxos, fitted to my STM (which already has the 'MonSTer' card fitted)


The kit - the edge connector is now pre-soldered
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Shifter riser soldering
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Socket for shifter soldering
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This is where it's going, an old STM. Note the spring clip on the MMU, this needs to be removed!
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Shifter - socketed, which is a relief :)
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Shifter board fitted
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Shifter re-added
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MMU board in place - difficult to make out, but it won't fit with the MonSTer board in place
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MMU board in place - difficult to make out, but it won't fit with the MonSTer board in place
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So, with the MonSTer popped out, I tried to fit it, but DISASTER! I has the pins set one too far back and my excitement to fit it, I pressed so hard that the back two pins popped through. I thought this would trash the board, but a very careful re-solder seems to have kept it alive, a lucky escape!
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MonSTer board back in as well
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Two resistors need cutting and given 5v+, 133 in this pic
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R134 in this (blurry) pic
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Linked to the 5v+ pin of the big capacitor
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overview of cable layout
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Bootup RAM test looks good ...
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And a few runs on a proper RAM tester also look good, so happy days
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'modification list' updated :)
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Link to bigger pics here: http://www.spiny.org/atari/photos/exxos_4meg_stm/

So this is now a 4 Meg STM with 8 Meg TT Ram on the MonSTer card and IDE to CF hard drives. While typing this the RTC turned up too, so another thread for that later :)
chad5200
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Re: [PICS] Exxos 4 Meg RAM card - STM edition

Post by chad5200 »

I also have an STM, but mine is REV. B (and yours is REV. H).

When it comes to disabling the existing RAM, you are showing that R133 and R134 (located just above the row of RAM) need to be lifted and tied to +5V.

However, my motherboard revision does not have these resistors. See attached pictures.

Does anyone know what I should do on my motherboard to disable the RAM?

Image

Image

Links to High Res images:

https://ibb.co/4Rc2tNw

https://ibb.co/XW7gq29
artik-wroc
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Re: [PICS] Exxos 4 Meg RAM card - STM edition

Post by artik-wroc »

chad5200 wrote:Does anyone know what I should do on my motherboard to disable the RAM?
Remove the choke on the right side?
chad5200
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Re: [PICS] Exxos 4 Meg RAM card - STM edition

Post by chad5200 »

I figured it out. The two 68ohm resistors (that are R133 and R134 on later motherboard revisions) are on the BOTTOM side of the motherboard and were installed in the factory.

Image

Here is a link to higher resolution:
https://ibb.co/NjW3S5M

Those two resistors and the jumper wire were all installed in the factory.
plee1024
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Re: [PICS] Exxos 4 Meg RAM card - STM edition

Post by plee1024 »

chad5200 wrote:I figured it out. The two 68ohm resistors (that are R133 and R134 on later motherboard revisions) are on the BOTTOM side of the motherboard and were installed in the factory.

Image

Here is a link to higher resolution:
https://ibb.co/NjW3S5M

Those two resistors and the jumper wire were all installed in the factory.
Chad, what did you end up doing? I have the same MB rev. B, was thinking to doing the mem upgrade.
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