XEGS Base Unit Upgrade

[Overange]

XEGS Base Unit Upgrade

 

Having acquired a working XEGS base Unit, with no accessories, I decide to do a simple 'PIMP MY ATARI 8-BIT', well sort of....

 

The unit itself worked when I got it, but the case had two PCB standoffs broken away, so I designed and 3D printed two Pillars and glued them in place.

Main Board Mods

Increased Memory.

 

Installed TFHH's 512 KB SRAM Memory Expansion V4.5, very easy to install, only had to remove middle pillar from the lid, this meant also using a nut and bolt to hold down the main board to the Case.

 

As part of the 512K installation you have to lift some IC Legs and solder onto the bent up legs, I am not a fan of doing this, so my solution is a small winged PCB soldered onto machined IC Sockets, then you can Tag on to your desired pin or, file away the pins if it’s not required to be connected to the main board.

These wings can be great for keeping installations tidy and reversable if needed, or even to create test points.

 

 

 

Upgraded the Audio to Stereo Output and incorporate PS2 Keyboard connection.

 

I had a spare POKEY chip, so I used Myteks TK-II-STEREO Fully Integrated PS/2 Keyboard and Stereo Sound Board.

However, I also wanted to upgrade the video output at the same time, so I fitted Myteks UGV, this meant I had to design a new PCB to incorporate the video and stereo output and include the Keyboard PS2 connection on the same PCB.

This is where I came up with a PCB that can be used on both the XL and XE Systems when the RF modulator is removed.

All you have to do is solder the headers, Video and keyboard connectors, to the side of the PCB that its intended for, The silk screen tells you which pins to use.

The 8 Pin Mini Din video standard I used is XRGB Mini. At the time of designing, I could of used one of the other video mini din connection types, but not knowing if the board was going to work or not and already having a premade XRGB Scart Lead and some 8 pin mini din PCB Connectors, I went with the XRGB design.

Having the optional PS2 Keyboard connector and with it being a one board design, it can be use on any of the XL or XE systems with some drilling required for the Keyboard Connector.

 

 

One problem I did encounter with the UGV in the XEGS, is that with the 512K expansion, it had to be stacked up higher using sockets to ensure it did not foul the 512K PCB, lucky the XEGS Case allows this...

 

Switching From Stereo to Mono.

 

When installing the TK-II Stereo PCB, a thought was how do I Switch it from Mono to Stereo or vice versa?

I did not want to install a Toggle switch, so I used a pre-existing Switchless Mod Circuit and changed it to work on the Atari’s.

 

I built a prototype to prove the concept, it worked as expected, so designed a PCB for it.

 

What should I call it?? well, its switches and I just been watching the Witcher on Netflix so its called....

 

'The Switcher'

 

Its basically wired into the reset switch circuit, and replacing the Power LED with a Bicolour LED, it can change colour to indicate its current state.

In this case Blue = Stereo, Green = Mono

 

 

To operate, all you do is hold down reset and wait for the LED to start blinking, when it changes to the state you wish to use, you simply let go and it saves this state. In turn this is switching the TK-II Stereo on or off.

 

 

Technically, it can be used on any of the other switches if required and switch anything else on or off.

 

The keyboard I found on Facebook market place for £10 including delivery.

 

The joystick was a PC Compatible Competition Pro with the 15 way connection, So I stripped it out and rewired it with a 9 Way.

 

One big thing I learnt from this is that when you undertake these upgrades is to:-

 

'Always read the manual'

 

Both TFHH and Myteks Instructions are spot on.

 

[_The Doctor__]

Your AVGcart can supply true SIO with the proper cable, and if you pick up the internal signal points you could make a custom ECI cable... that would give you a memory upgrade directly from the AVGcart.

[Overange]

6 hours ago, _The Doctor__ said:

Your AVGcart can supply true SIO with the proper cable, and if you pick up the internal signal points you could make a custom ECI cable... that would give you a memory upgrade directly from the AVGcart.

I do have the SIO, XL ECI and XE ECI cables for the AVGcart, I did consider tapping out the signals from the XEGS for the extended memory, but decided to go with TFHH's memory Board.

[bfollowell]

Wow! That's a lot of work for a new member with only four posts to their name, two of them in this thread. Usually, it takes a handful of posts just for people to get around to inquiring about what sorts of upgrades they should consider. Excellent work!

 

[mimo]

Really nice upgrades.

Do you have a make / model number for the keyboard?

I've got 2 xegs here with no keyboards 

[TZJB]

Really nice and neat upgrades. You certainly have some skills regarding board design. I like the IC wings concept, it makes the connections that much stronger I would think. But no-one has a spare POKEY chip, surely? 😉

 

Do you have any other upgraded Ataris, and are you considering sharing your board designs to the public?

 

I quite like the TFHH 512K SRAM memory expansion too, although I bought that before the AVGCART so technically I no longer need it. It's good to have the choice though.

[Overange]

 

Thanks for the comments  

 

The keyboard is a BTC 5100C

 

I have always been into Electronics and Computers since a kid, my first computer was an 800xl, so Atari has a bit in my heart.

I served my apprenticeship in Electrical Electronic Engineering back in the mid 90s, so spent a while in design, build, coding and servicing of Electronic Systems. So, I tend to look at something and research it myself to get a better understanding of how it works, then look to see if it the solution I need, if not I will adapt another design, or design my own.

If I do get really stuck, then I ask.

In the last year, following a change in my job, it has meant I now have a little more hobby time and then the Retro Electronics spark hit me.

I do generally keep myself to myself, but sometimes will join in.

 

My Atari Collection

I have a 65XE reissue that I have just finished building the Main Board, but will look to implement some of the more modern upgrades into it at some point.

An original 800XL, going to clean it up and keep as original untouched.

The modded XEGS

An original near complete XEGS, again will clean up and keep original.

 

I do have other retro computers 😛 

 

Once I am happy with the designs and I feel its time to share, I will provide access to them.

 

If anybody whats to try the IC Wings, please let me know  😊 

 

It has amazed me as to how much the community is keeping these old systems alive and the development of new software and hardware is amazing.

 

 

 

 

 

[+x=usr(1536)]

46 minutes ago, Overange said:

If anybody whats to try the IC Wings, please let me know

Definitely interested 

 

Nice job, BTW.  Like the stereo selection method.

[+David_P]

11 hours ago, mimo said:

Really nice upgrades.

Do you have a make / model number for the keyboard?

I've got 2 xegs here with no keyboards 

You can roll your own https://ataribits.weebly.com/tk-ii.html, or buy a PS2 to XEGS adapter  https://thebrewingacademy.com/products/tk-ii-xegs-s-ps-2-for-xegs-keyboard-replacement

 

 

[+mytek]

Nice job 👍

 

And I love the 'winged' IC socket idea and implementation. Great stuff and very useful.

 

Edit: and the stereo/mono 'switcher' you came up with is quite ingenious!

[mimo]

54 minutes ago, David_P said:

You can roll your own https://ataribits.weebly.com/tk-ii.html, or buy a PS2 to XEGS adapter  https://thebrewingacademy.com/products/tk-ii-xegs-s-ps-2-for-xegs-keyboard-replacement

 

 

Yeah, I've made a few tk2 GS boards, I just like the look of the keyboard, thanks 

[Overange]

On 4/15/2023 at 11:30 PM, mytek said:

Nice job 👍

 

And I love the 'winged' IC socket idea and implementation. Great stuff and very useful.

 

Edit: and the stereo/mono 'switcher' you came up with is quite ingenious!

Thanks, I modded an opensource design, however as that design only gave a 5V switched output, I wanted to have a true switched circuit so I added an Opto-Isolator.

It does mean it could be utilised to turn on or off other devices.

 

The IC Wings has been uploaded to PCBWAY Projects, if anyone wants any?

 

https://www.pcbway.com/project/shareproject/Pinout_20_IC_Wings_A_tidy_way_of_connecting_to_IC_Chips_to_help_with_retro_69a976d7.html

 

To get the best out the order, I found the maximum you can have before the price jumps up is 40 Strips for $5usd then its about $5 usb 8 day delivery.

Also ensure you set the board thickness to 0.8mm.

 

thanks