Atari 130XE Remake

[+ZuluGula]

4 minutes ago, santosp said:

Also if I understand good the above pcb is in ITX form, who isn't the subject here.

Yes, I understand it. 

I just put it here to show that you don't need 4 layer pcb, SRAM memory or UAV to fix XE video issues. Anyway, you will have to build some additional circuit to restore Composite signal after you remove RF modulator. I would like to see in the place of the modular a DVI port with a connector to Sophia, you know, something that replaces the little board that comes with Sophia.

[kenames99]

1 hour ago, ZuluGula said:

 

This XE board has two layers pcb and has great video quality without UAV. 

Never design any board that require properiary devices to make it functional. 

where can we get that board from? it looks so cool.

 

Ken

 

[santosp]

The progress till now, using the Atari 's funny pcb marking for the ic components placement. This isn't so professionally but I go so mainly for the accuracy with the original.?

 

In order to get accurate measurements, I had to find a  board from it and detach almost all the components except the passive ones. 

Fortunately, one was found from the ebay of Slovakia, and although the most main ic parts was already missed, finally fulfilled the purpose for which it was purchased.

 

 

 

[Krenath]

Oh, I SO need this for my old 130XE.  

 

[danwinslow]

i think this is a great idea, and would buy several. As others have said, UAV and a hdmi output would be good, I'd like to see a fixed up PBI/ECI especially if it had buffering and some kind of a pin-out or cable socket such that we could interface things more easily. More ram is a great idea...not sure why we wouldn't just go to 1MB but any RAM expansion beyond 128 would be great.

[_The Doctor__]

@santosp

keeping all 16 will allow the greater number of people to move 130XE components lock stock and barrel (as the most boards are in this configuration and memory is cheap), and makes for a fast rebuild rather than waiting for parts (at least in the USA)

many memory upgrades are built on the 16 dram chip format of the board as well.

You can snag a memory chip out of another known good machine such as an 800XL at will and troubleshoot your own XE

Also consider if a bank fails a quick switch of the bank address line get you going again, the fix is often a single dram chip or two. You can almost always find 8 that are good from those 16 to keep the machine running until new ones arrive. With other solutions you are down until you can get the parts delivered (delivery from china these days can be interesting).

SYSCHECK and other memory testers shows you what chip may have failed

Just one more set of reasons to go the 16 dram chip route

 

Hope some of this is helpful

Edited February 7, 2021 by _The Doctor__

[flashjazzcat]

41464s are cheap and you only need four of them for 128K. I'd rather diagnose main memory issues by swapping out two DRAMs than eight. I don't know what the problem is there.

[+DjayBee]

Where is the additional value of needing old RAMs which eventually will fail to populate the board instead of a dirt-cheap SRAM chip?

 

There the additional value would be an out-of-the-box 512 KB RAM extension.

[Mathy]

Hello Panos

 

This might be a stupid idea, but: Would there be room enough on the board to have through holes for both the four chip AND the 16 chip RAM?  Of course, there's no need to use both at the same time, but with holes for the four chip and the 16 chip version, the user could choose to use either 4 RAM chips or 16 RAM chips, depending on what (s)he prefers.  The 16 chip version would cover (part of the) 4 chip holes and the 4 chip version would cover (part of) the 16 chip holes.

 

Sincerely

 

Mathy

 

[_The Doctor__]

I think the idea was a drop in replacement board with little or no need to buy any other kind of parts, fixing up all the cost reduction and bodges to give us a solid foundation to build on, instead of the constantly cost reduced flimsy trace pcb the tramiels gave us.

for instance adding back in some of the original timing circuit clean up the video a bit, all of the traces and pads are there, it just needed a partial re population. leaving both available give the end user a choice to go either way. another is the bodge wires that deal with a timing issue or other mistake, getting rid of those is a very nice thing.

 

*edit* part of what is talked about is obsoleted as @Mathy has a really really great solution!

and in fact convenient upgrade holes for header and the like is a very nice touch as well

 

everyone here are really sharing their experience and it's wonderful

Edited February 7, 2021 by _The Doctor__

[foft]

Would be great for upgrades to include a few pin headers for all the useful pins. D0-D7, A0-A15, AN0-2, HALT, PHI2, OSC, COL, HUE etc. Or perhaps a pin header footprint next to each main chip.

[+MrFish]

21 minutes ago, DjayBee said:

Where is the additional value of needing old RAMs which eventually will fail to populate the board instead of a dirt-cheap SRAM chip?

 

There the additional value would be an out-of-the-box 512 KB RAM extension.

I don't see the need either, if you start with extra RAM on the board. That's one reason why I listed it on my suggestions.

 

Edited February 7, 2021 by MrFish

[Mathy]

Hello foft

 

3 minutes ago, foft said:

Would be great for upgrades to include a few pin headers for all the useful pins. D0-D7, A0-A15, AN0-2, HALT, PHI2, OSC, COL, HUE etc. Or perhaps a pin header footprint next to each main chip.

 

Isn't that kinda what I said here in number 17?

 

Sincerely

 

Mathy

 

[+kheller2]

So while we are at it, we are going to do the 128K 800XL board?  ?

 

I think 1450XLD plastics with a new MX keyboard is in order too.  Shame molds are so expensive. 
 

I wonder what creative designs one could come up with for a 130XED case.  

[adam242]

I'd like to see this with UAV built in, 1meg RAM, and a socket for second POKEY stereo. I'd buy at least one.

[+MrFish]

16 minutes ago, adam242 said:

...and a socket for second POKEY stereo.

 

Ah, I knew I forgot something. I'll agree with this suggestion.

 

[+ZuluGula]

Since there's PokeyMAX, I don't think it's necessary to add place for second Pokey. 

[+MrFish]

8 minutes ago, ZuluGula said:

Since there's PokeyMAX, I don't think it's necessary to add place for second Pokey. 

POKEYMax is a great little device; but I'm interested in using 2 real POKEY chips.

 

[flashjazzcat]

Having two POKEY chips would imply that the additonal circuitry for stereo POKEY was also present on the motherboard (as per the 1088XEL). Most dual-POKEY boards have the stereo circuitry on the board, and require only one POKEY socket on the motherboard.

Edited February 7, 2021 by flashjazzcat

[+MrFish]

2 minutes ago, flashjazzcat said:

Having two POKEY chips would imply that the additonal circuitry for stereo POKEY was also present on the motherboard (as per the 1088XEL). Most dual-POKEY boards have the stereo circuitry on the board, and require only one POKEY socket on the motherboard.

 

Yes, true. I like the idea of having it on the motherboard, same as with the extra RAM; and preferably the same with improved video circuitry as well.

 

[flashjazzcat]

There are things I would like to see as well (vias for a DIN13 for VBXE, etc), but for this reason I do not envy santosp here, since everyone will be projecting their requirements onto the design. If you hard-code Gumby Stereo into the motherboard, people will complain that they cannot use their PokeyMAX with quad-POKEY, dual SID, Covox and PSG, etc.

 

[BillC]

2 hours ago, Mathy said:

Hello Panos

 

This might be a stupid idea, but: Would there be room enough on the board to have through holes for both the four chip AND the 16 chip RAM?  Of course, there's no need to use both at the same time, but with holes for the four chip and the 16 chip version, the user could choose to use either 4 RAM chips or 16 RAM chips, depending on what (s)he prefers.  The 16 chip version would cover (part of the) 4 chip holes and the 4 chip version would cover (part of) the 16 chip holes.

 

Sincerely

 

Mathy

If staying with DRAM instead of changing to SRAM there is one major advantage of the 8 x 4164 configuration for the extended memory bank.

This is the ability to replace the 4164 with 41256 if considering an old style memory upgrade.

 

PS: Possibly include the circuitry for a 320XE memory upgrade using 41256 DRAM in the extended bank.

Edited February 7, 2021 by BillC

[+MrFish]

Well, the forum's open; so, let 'em complain.

 

If Santosp didn't wan't hear conflicting concerns, he wouldn't have invited all opinions.

 

[Mathy]

Hello guys

 

44 minutes ago, flashjazzcat said:

If you hard-code Gumby Stereo into the motherboard, people will complain that they cannot use their PokeyMAX with quad-POKEY, dual SID, Covox and PSG, etc.

 

That's why I want pick up point (through holes) for the chip select signals.  That way, you can choose between piggybacking the second Pokey, using a Dual Pokey Board or installing a PokeyMax.

 

Sincerely

 

Mathy

 

[Mathy]

Hello guys

 

26 minutes ago, BillC said:

PS: Possibly include the circuitry for a 320XE memory upgrade using 41256 DRAM in the extended bank.

 

Similar to what Atari did on many 65XE's and all the 800XE's that came with 130XE PCBs.  You just have to desolder three zero-Ohm resistors, solder in a socket and stick in the CO25953 to upgrade them to 128kB of RAM.  The new PCB would have this and some circuitry to go to 320kB, preferably without using bits 4 and 5 to select memory banks.

 

Sincerely

 

Mathy