CO700115 REV. 2B with Piggyback RAM expansion.

ST & STM motherboards.
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rubber_jonnie
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CO700115 REV. 2B with Piggyback RAM expansion.

Post by rubber_jonnie » Thu Nov 22, 2018 9:27 am

It's a REV. 2B and it has a piggyback RAM expansion.
IMG_20181121_200227.jpg
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IMG_20181121_200206.jpg
IMG_20181121_200206.jpg (5.12 MiB) Viewed 327 times
I will update when I get a chance to give it the once over and power it up.

Anybody else think those wires look like telephone cable?
Collector of old Atari things:
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Re: CO700115 with Piggyback RAM expansion.

Post by troed » Thu Nov 22, 2018 10:12 am

rubber_jonnie wrote:
Thu Nov 22, 2018 9:27 am
I can't quite make out the revision, I will update when I have it apart again, but it has a piggyback RAM expansion.

Anybody else think those wires look like telephone cable?
Very very early motherboard - no filters.

And yes, that's typical extracted wires from a telephone extension - I've used them as well (single core, nice stiffness) for similar work. Might even have used them for my own piggyback extension IIRC :D

Not an official Atari upgrade, never seen them using them.

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Re: CO700115 with Piggyback RAM expansion.

Post by rubber_jonnie » Thu Nov 22, 2018 10:18 am

troed wrote:
Thu Nov 22, 2018 10:12 am
rubber_jonnie wrote:
Thu Nov 22, 2018 9:27 am
I can't quite make out the revision, I will update when I have it apart again, but it has a piggyback RAM expansion.

Anybody else think those wires look like telephone cable?
Very very early motherboard - no filters.

And yes, that's typical extracted wires from a telephone extension - I've used them as well (single core, nice stiffness) for similar work. Might even have used them for my own piggyback extension IIRC :D

Not an official Atari upgrade, never seen them using them.
Whoever did it seems to have known what they were doing, as it looks quite neat. I'm assuming it's an upgrade to 1MB, but won't know until I get it running. According to exxos, who I bought it off, it powers on but doesn't boot, so I may have work to do before I get any more detail on it. Guessing it will have a pretty low ROM version.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
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Re: CO700115 REV. 2B with Piggyback RAM expansion.

Post by rubber_jonnie » Sun Nov 25, 2018 12:27 pm

Taken apart this morning, not powered on as yet.

Here is the other end of the telephone cable:
IMG_20181125_122321.jpg
IMG_20181125_122321.jpg (6.6 MiB) Viewed 270 times
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: CO700115 REV. 2B with Piggyback RAM expansion.

Post by rubber_jonnie » Wed Nov 28, 2018 9:27 pm

Looks like this board has a memory problem, powers on and gets a white screen with blotches on it. Time to buzz out the lines and/or remove the piggy back ram.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
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Re: CO700115 REV. 2B with Piggyback RAM expansion.

Post by rubber_jonnie » Fri Dec 07, 2018 5:06 pm

So piggyback RAM expansion is now gone, And I have adjusted the MMU PLCC socket springs so that they are making proper contact with the MMU.

I might just do a quick article on adjusting the springs in a PLCC socket, as this is the second machine that I've had that has benefitted from it.

I also had to fix 3 cut tracks from the MMU too. Thank you kynar wire for being so fine :)

But, it lives again:
It_Lives!.jpg
It_Lives!.jpg (333.03 KiB) Viewed 159 times
Test cart shows the remaining RAM is good, and I'm looking at TOS v1.0.

If I want to add more RAM in the future, I have a 2meg board that would do just nicely, but for now I'll take this as a win.

And as for the mouse/joystick port position, they are SOOO much better on these earlier machines, not sure what Atari were thinking when they slapped them under the keyboard. Also odd, but the mouse doesn't work if there is no keyboard plugged in. Go figure.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
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Re: CO700115 REV. 2B with Piggyback RAM expansion.

Post by exxos » Fri Dec 07, 2018 5:15 pm

:bravo:

rubber_jonnie wrote:
Fri Dec 07, 2018 5:06 pm
I might just do a quick article on adjusting the springs in a PLCC socket, as this is the second machine that I've had that has benefitted from it.
That would be useful!
rubber_jonnie wrote:
Fri Dec 07, 2018 5:06 pm
Also odd, but the mouse doesn't work if there is no keyboard plugged in. Go figure.
I assume it needs the keyboard chip to convert the data from the ports into serial for the ACIA, which is why the connector is so large.
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Re: CO700115 REV. 2B with Piggyback RAM expansion.

Post by rubber_jonnie » Fri Dec 07, 2018 5:25 pm

exxos wrote:
Fri Dec 07, 2018 5:15 pm
:bravo:

rubber_jonnie wrote:
Fri Dec 07, 2018 5:06 pm
I might just do a quick article on adjusting the springs in a PLCC socket, as this is the second machine that I've had that has benefitted from it.
That would be useful! I shall do one at some point then :)
rubber_jonnie wrote:
Fri Dec 07, 2018 5:06 pm
Also odd, but the mouse doesn't work if there is no keyboard plugged in. Go figure.
I assume it needs the keyboard chip to convert the data from the ports into serial for the ACIA, which is why the connector is so large. My thoughts too. It just behaves really weird with no KB.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: CO700115 REV. 2B with Piggyback RAM expansion.

Post by rubber_jonnie » Tue Dec 11, 2018 9:10 am

Damn, something is not right, after cleaning up the legs that were soldered onto the existing RAM, I'm getting the same screen corruption and its not booting.

Magnifying glass out to see if the MMU has any dodgy connections at the socket, plus a clean of the pins, and if there are any solder whiskers left over.

Looks very like a problem I had with an STFM that showed garbage on screen and wouldn't boot, and that was a couple of address lines that weren't connecting all the way through, so a buzz of all the RAM chip lines may help.

May also be a problem with the lines that were cut that I had to repair, so will look at those again.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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