Atari 130XE Remake

[santosp]

Hello to all.

I have started to work in a remake of Atari 130XE pcb board, more specific with the 4 rams.

The main reason who I started is because I never seen  someone else before to do this for the XE range.

Many things run in my head about the final design of this pcb board. 

Must be a 1/1 remake like the original? Maybe  with smd components for the passives like resistors, capacitors and diodes? Maybe with a cpld which equates Freddie and both the Gals; 

Or is better this to be exact the same like the original pcb, so to be possible after for the new owner to add any upgrades?

Even so would be more usefull if I add on the UAV mod in the place who initially was the rf modulator?

 

At the end, is needed to do this remake at all?????

 

I would like very much to listen your thoughts and ideas about this. 

Whether positive or negative they are all welcome. 

[+MrFish]

I think it's a great idea. I'd buy at least a pair if they were made.

 

My initial thoughts are:

1. UAV would be nice

2. Any amount of extra RAM (320 - 1MB) would be desirable

3. Using SMD's & CPLD is fine

 

There's a thread on here where someone was going to do a 1 to 1 remake of the board only (for better quality). He did hi-res scans of both sides of the PCB; but I can't seem to locate the thread or the files he uploaded yet (I'm sure I downloaded them). Might be some help to you. I'll try and search again later.

 

Edited February 6, 2021 by MrFish

[_The Doctor__]

a remake could help those who have damage their Atari's doing upgrades, so with better quality traces the XE could really improve. Taking care to pick the best parts of the revisions that were made to the PCB and incorporate them along with better power rails to the video circuits etc, and good shield planes... Maybe while your at it incorporating the video fixes and other mods on the pcb so we are running bodge wires for this or that, built in fixes! Just thinking about how adding the alternative timing circuit back in also helped the XE's video. The XE revs were such a mixed bag, luckily all the nuances and fixes a documented in one way or another. Maybe we could add the most useful signals back to the ECI or just give it an enhanced pbi card edge folding the most useful eci signal back to pbi without breaking anything if some crazy person sticks a 1064 on it to 'see what happens'

 

You asked

 

base 64+128=192k/320 (with address line added) is cake although I always wanted to try 128K in the first bank of 8 and 128k in the second bank of 8 to see if I could get 256 separate antic access in some transparent way as 192k works that way. 64+256=320k was handled as ANTIC following but I think everything out there still worked

 

_T D__

Edited February 6, 2021 by _The Doctor__

[+MrFish]

9 minutes ago, MrFish said:

He did hi-res scans of both sides of the PCB; but I can't seem to locate the thread or the files he uploaded yet (I'm sure I downloaded them).

 

Alright, I found them. Contains pictures and scans.

 

130XE Desoldered MB.zip

 

[archeocomp]

Why do you not want to use 128k one chip SRAM? That would make schematics more simple and provide for cleaner TV signal.

[_The Doctor__]

I like the idea of a replacement board, a complete redo down to the memory type and architecture is a whole different project akin to the other projects already done.

[ivop]

Try to not rely on any third party upgrades. Everything on board. RAM, ROM, MMU, and a proper video out circuit. That would be my advice

 

You could use SMD parts, but I wouldn't go smaller than 0812, and 50 mil pins, so it can still be hand soldered.

 

[Voxel]

Sounds very interesting.  I hope it has expandable possibilities too, and on that note from a DIY angle can the traces on the board be a good size, as modern devices tend to have really thin traces, so makes it fiddly for me to work on them.

[+gnusto]

A shell compatible (mounts in the existing shell, reasonable cable routing to existing ports) would be a great idea to me, if it came with upgrades. The 130XE is on the low end of build quality in 8bits, and there should be more and more dead ones each year nowadays.

 

Actually that + a keyboard upgrade for the 130xe would be a great machine for me personally. Visual look of an Atari with modern components, form factor does matter some.

[RodLightning]

A drop in replacement for those original boards would be welcome.  Tramiel era cheap PCB materials and MT memory failures have plagued the 130XE for so long.  Completely agree about third party upgrades.  Fixing problems with the original would be enough, however you went about it.

[BillC]

1 hour ago, archeocomp said:

Why do you not want to use 128k one chip SRAM? That would make schematics more simple and provide for cleaner TV signal.

And would save space and reduce cost, Mouser sells a 128KB 32-pin SRAM for ~$4, this would eliminate address multiplexer and refresh circuits.

https://www.mouser.ca/ProductDetail/Alliance-Memory/AS6C1008-55PCN/?qs=E5c5%2Bmu3i39qb4Qta5D2qg%3D%3D

 

Mytek has also posted a simplified schematic of what is required to use a 64KB SRAM, a single 14-pin IC.

He has used a 64KB UM61512A SRAM for base RAM in 3 projects, his 576NUC+ project also uses a 512KB ASC6C4008-55PCN for extended RAM. 

 

[NISMOPC]

I think this is a fantastic idea. between a new (modern) board and a mechanical keyboard, it's what the 130XE coulda been. I have been following this keyboard upgrade since day one. Praying it comes out for purchase...

 

...and yes those are Chery MX blue switches on a custom PCB.

 

Atari 8bit Upgrades & Repair | Facebook

[+MrFish]

27 minutes ago, NISMOPC said:

I think this is a fantastic idea. between a new (modern) board and a mechanical keyboard, it's what the 130XE coulda been. I have been following this keyboard upgrade since day one. Praying it comes out for purchase...

 

...and yes those are Chery MX blue switches on a custom PCB.

 

Atari 8bit Upgrades & Repair | Facebook

 

A little over-the-top on keycap colors; but a new keyboard combined with a new motherboard would be a great combo.

 

[_The Doctor__]

I think the last time I bought drams it was 100 pieces for $18.00 shipped to my door, chips for 256k were 50 fo 16.00 not sure what ebay shows these days, but bulk orders like this should still be possible. They came from china and worked as they should, probably pulls from old equipment but couldn't tell.

Edited February 6, 2021 by _The Doctor__

[Mathy]

Hello MrFish

 

33 minutes ago, MrFish said:

A little over-the-top on keycap colors; but a new keyboard combined with a new motherboard would be a great combo.

 

This is what the guy working on it says about it:

 

Quote

Frankenstein keyboard! Due to a misaligned function keys, they are not installable with the actual cover. They are already corrected in the V2 of the PCB. The keycaps are OEM profile from a donor keyboard. They work great! Awesome stuff indeed. Next step is paint them all in oyster white and work for some legends. After that, I will try the lower profile DSA and new legends too!

 

Sincerely

 

Mathy

 

[kenames99]

3 hours ago, MrFish said:

 

Alright, I found them. Contains pictures and scans.

 

130XE Desoldered MB.zip 8.18 MB · 8 downloads

 

wow, really great that you found this and reposted it. thanks for your efforts.

 

also I would really like to see this mb reproduced. I would buy a couple. I would like to see exact replacements tho, complete with the 16 ram chip placements, like most USA boards were.

 

Ken

 

Edited February 6, 2021 by kenames99

[Mathy]

Helo Santos

 

As some guys already mentioned, fix what the Tramiels did wrong.  Don't put a UAV in, but improve the video circuit so the picture quality is equal to that of the UAV.  Maybe add extra through holes under the DIN video connector, so those who want to can install a DIN connector that will accept the standard video plug, but also a plug with more pins, for instance for stereo out.  Maybe add the holes for the RF modulator, but also some other holes for other stuff people might want to put there.  Maybe just holes to mechanically secure some little PCB (like for instance the Sophia x)  to the motherboard.   Using SMD parts instead of the usual resistors, diodes, etc. might create some space for extra options, or just a connector with signals that might come in handy when upgrading the computer.  But please don't replace the Atari specific chips and the RAMs.  All current upgrades are designed to fit on the motherboard Atari gave us.  Changing these would mean that a lot of upgrades would have to be converted too. But it would be nice if we could have some extra through holes for picking up chip select signals, so you don't have to solder wires to chips directly.

 

BTW you can find the original schematics on my Docs page.

 

Sincerely

 

Mathy

 

[+MrFish]

5 minutes ago, Mathy said:

As some guys already mentioned, fix what the Tramiels did wrong.  Don't put a UAV in, but improve the video circuit so the picture quality is equal to that of the UAV.

 

I agree that an updated circuit providing UAV quality would be preferable -- as long as it's not too much overall trouble; but I'd rather have a straight ahead UAV board in there than no change whatsoever.

 

[santosp]

 

Thank you all for your replies on the subject. ?

Really I got very useful things and knowledge from you, and I am sure that I will get more when it needed. 

Such as some of you I am closer to the idea for a pcb design like the original from the Atari. Why?

Because I am sure that many XE owners who will decide to change their motherborads they will already have some add-ons,  will want to use them again. 

So if I made modifications on the pcb board and in the components, my previous reasoning may be not feasible at all.

 

Also how do you see the idea to use the same ram implementation with the four ic, like did the Atari on her mainboard?  Even this is a step to simplify the design of the board. 

 

I read in your messages that you speak for a cleaner video signal output. I thought that this will be solved with a "UAV" designed on board. If not, can someone propose what else needs to be changed exactly in the design to have a better result? 
Maybe a four layer design with independent ground and voltage planes? Or is not so crucial and with some other tricks we can avoid those damned screen bars and any other noises there.

 

[santosp]

47 minutes ago, kenames99 said:

. I would like to see exact replacements tho, complete with the 16 ram chip placements, like most USA boards were.

 

Ken

 

Hi Ken,

why is better to go with 16 ram ic's and not with 4 only?

I see some lots on ebay lets say from Sanyo (LH2464) at 5.5 euro per 5 pieces.

Edited February 6, 2021 by santosp

[OmaOhneBH]

Internal Fujinet maybe?

[RodLightning]

UAV type video circuit designed on the board is the best idea.  Some of us were maybe picturing a header where we need to plug in existing UAV board.

 

128kb ram with four chips is the right path, in my opinion, with fewer points of failure present.  I can't deny the allure of SRAM instead, but I get the feeling you are leaning towards a legacy design.  In that case, the four chip version Atari used would be fine.

 

Edit: Freddie is in short supply these days, a CPLD to replace it and associated logic is welcome.  I would be happy if Sally, Antic, Pokey, GTIA and maybe PIA were the only donor chips required from old hardware.

Edited February 6, 2021 by RodLightning

[ZuluGula]

 

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. 

[santosp]

Just to clarify that when we speak for UAV board, we mean as a permanent design in pcb board on the empty space in rf modulator area. Not a add-on which will needed as an extra device to be working the motherboard.

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

[kenames99]

1 hour ago, santosp said:

Hi Ken,

why is better to go with 16 ram ic's and not with 4 only?

I see some lots on ebay lets say from Sanyo (LH2464) at 5.5 euro per 5 pieces.

hi Santos, most USA boards had the 16 chip design. all the 130xe machines I have seen are 16 chip. I myself have a stock of over 200 256K ram chips for replacement and am sure more than a few people have some of the 16 pin 64k x 1 or 256k x 1 chips.  But since you are doing this the final choice is yours and I will buy at least 2 either way. thanks.

 

Ken