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1088XEL Alternative Mother-Board Project

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So Just having checked the fit of the UM1B that i have i will need to desolder the right angle headers and install straight headers to install it. And i assume P2, P2 and P4 will have to be moved to the other side of the UM1B board as they will be problematic otherwise.

 

Douglas

 

Nope. Remember, the U1MB goes in upside down (battery on top). All the headers then plug into the female headers on the 1088XEL mainboard.

 

post-30400-0-49495600-1537110600_thumb.jpg

 

post-30400-0-19050100-1537110607_thumb.jpg

Edited by DrVenkman
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I spoke with Lotharek a few weeks ago about the possibility of getting U1MB boards already stuffed with all vertical instead of right-angle headers and he seemed open to the idea, but more negotiation will be required to firm this up.

 

csYzmHH.jpg

 

I can't fully describe what a great feeling it is to simply plug this into the XEL without fussing with ribbon cables and mounting screws. And due to the R&D nature of the first run boards, I have had to remove and replace this numerous times, with each time bringing a smile to my face :)

 

- Michael

 

Its killin' me! I am slowly removing pin for pin the angled header connections in the hopes that i don't destroy the board or chips.

 

I need the correct header arrangement to even go forward.

 

Arrghhh

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I believe there is room to make it fairly thick, since the motherboard mounting allows space between it and the back of the enclosure. I'll check this out better when i actually get around to creating the CAD file.

 

------------------------

Project Update

------------------------

The Version 1.1 PCB file which contains fixes for the problems such as the transposed 6520 PIA address lines and the Power-Up Reset, has now been completed. I'll be making a small run to verify everything, but will be holding off on doing so until my beta testers have had time to run their own tests. I'll also hold off on posting the updated schematics until things look pretty solid and locked in, no sense in having multiple sub version documents of this production version out there in the wild.

 

One of the highlights of this new version will be a slightly expanded MPBI connector, which allows for adding a couple more signals that will prove very useful for later upgrades such as the Covox sound generation device that was talked about earlier. Here is a sneak peek at the new improved version (added Left and Right Audio Inputs and the /RST signal).

 

XFnFFf2.png

 

Also fixed the MMU and OSROM mis-routed signals, which wasn't an issue for the U1MB, but might have impacted a replacement daughter board. Speaking of which there has been talk on the Polish forums about possibly having a simple daughter board that would contain the standard MMU and OSROM (or some facsimile thereof). I also had this same thought, and will be looking into doing something like this down the road, once I figure out if I want to approach it in a simple way (just plug in Atari ROM and MMU) or maybe allow for multiple OS switching. However the idea is to keep it simple and inexpensive, thereby being a poor man's substitute for the U1MB board and not try to make it actually do what the U1MB does (what would be the point, the U1MB is a bargain for all that it does).

 

 

- Michael

 

 

First of all I wanted to express my insane amount of gratitude for what you have done. I have a green one and a blue one. I suppose the red ones were for the beta testers?

Can we get a serial number on these?

Anyway and I am sure it is mute as I am only half way thru the build info in the thread but.....

I need my MTV! I need my Atari keyboard!

Two days ago in 1984 Madonna sang virginistic and I became the third person with a personal computer to spend six months at sea on a westpac with a personal computer.

So I Iterate.

 

What can we do to use an atari keyboard in this build?

I am looking at the 1200XL and as i have seen so far it is the OS that likes your unit..

 

I dont need you to give me a version1.2 of your motherboard just an idea as to where do I wander.

 

BTW I was thinking of adding the circuits and 10 keybad CX-86 to the mix.

 

Worthy is not what I am!

 

Douglas

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The easiest way to add a stock keyboard, would be to go with either the one from the XEGS or the 1200XL, which both have the key matrix scanning circuits on-board. Then it would simply be a matter of connecting the appropriate pins to where they would normally go circuit-wise. I would suggest doing so with a connector of some sort between them, so that the keyboard could be easily disconnected if needed. To see what goes where, search for the schematics online to the systems these keyboards came from.

 

Keep in mind that the XEGS keyboard is probably the worse ever made, and the 1200XL although the best, has no enclosure. Personally I don't see the attraction, because now days everyone should be quite familiar with the key layout of a PC keyboard, thus making the transition from your PC to the A8 that less confusing if you use the same one for both.

 

You will also be giving up some of the functionality that the extra function keys bring, like the one key launch buttons for U1MB setup and the XEL Loader.

 

Thank you for the praise on the project, and I'm glad you are enjoying it :) .

 

1088XEL PCB History

 

The original V1.0 boards that went to the beta testers were blue. A total of 10 of those series were created, none of which got sold to the public. These required a lot of mods for full functionality, some of which were quite tricky to do. These boards very much lived up to the 'beta' name ;) .

 

The first V1.1 boards were made by me, and done with a green solder mask. I think only a couple of those ever got sold (not by me). Most of them went to the beta testers, a few went to MacRorie, and I think I still have about 6 of those out of the 15 that were produced in that first run.

 

When MacRorie took over production, his first boards were blue, and then later he offered green ones as well. I don't know how many of each are presently out in the wild.

 

Later a very small run of yellow boards were made by ZuluGula, with some being sold to people in Poland. And then later still, krisbA over in Poland also did a few red boards as well, which a few of those got put up on AmiBay. I'm sure more have since been made by other individuals in various countries.

 

post-42561-0-30647200-1537222799.jpg post-42561-0-34432600-1537223123.jpg

 

Serial numbers would have been nice, and I should have provided a rectangle in white silk screen on the board to allow writing one in. Something to keep in mind for other similar projects such as the 1088XLD if it ever goes public.

 

Those dammed right angle headers...

 

Flashjazzcat, Macrorie, and myself all tried to persuade Lotharek into switching back to vertical headers on the U1MB as it was once done in the past, but never succeeded in convincing him to do so. Feel free to try, maybe the more people that do, he'll begin to reconsider.

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1088XEL PCB History

 

 

When MacRorie took over production, his first boards were blue, and then later he offered green ones as well. I don't know how many of each are presently out in the wild.

There are currently (from me) 48 blue mother boards and 41 green motherboards in the wild. 23 were fully assembled by me. 8 were partially assembled by me. The balance were either DIY kits or bare boards.

 

Serial numbers would have been nice, and I should have provided a rectangle in white silk screen on the board to allow writing one in. Something to keep in mind for other similar projects such as the 1088XLD if it ever goes public.

Funny you should mention that as I was just in the process of looking for serial number plates. The one I am considering is attached.

Those dammed right angle headers...

 

Flashjazzcat, Macrorie, and myself all tried to persuade Lotharek into switching back to vertical headers on the U1MB as it was once done in the past, but never succeeded in convincing him to do so. Feel free to try, maybe the more people that do, he'll begin to reconsider.

Yap, he said he would consider it when he runs out of the current production run. Do not know when that will be, but he was pondering it.

post-16779-0-14948900-1537243076.png

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Wow almost 90 1088XELs, that's very impressive for the first year :thumbsup: .

 

I really like the serial number plate. Do you plan on sending those out to everyone you sold boards to? Be nice to have that as a permanent record as to the order they went out the door.

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Wow almost 90 1088XELs, that's very impressive for the first year :thumbsup: .

 

I really like the serial number plate. Do you plan on sending those out to everyone you sold boards to? Be nice to have that as a permanent record as to the order they went out the door.

That was my plan. I was going to contact everyone and let them know as soon as I had them completed. I have been meaning to do it for a bit now, just hadnt gotten a round twoit. ;-)

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Received 1st ProtoType MIDI-XEL PCBs Today

 

I'm still fiddling around with the value for the audio mix resistors... thinking of going with 33K (those are 39K shown in the photo). Edit: confirmed 33K resistors are to be specified for R1 & R2, 390 ohm for R3 in the final docs.

 

post-42561-0-38362400-1537312716.jpg

 

post-42561-0-63866300-1537312721_thumb.jpg

 

post-42561-0-66175300-1537312727_thumb.jpg

 

post-42561-0-84803100-1537312733_thumb.jpg

 

So this will fit in an 80 mm tall case, assuming there is nothing on the rear panel blocking it. But it won't fit vertically in my 60 mm case. Unfortunately it's just a little bit too tall. So I think I'll move the upper headers off to the side, which should get me down to where I need to be. Obviously there may be cases where a cable will need to be used instead (or Dropcheck's SIO-AUX expander board if she still makes that ;) ).

 

BTW, it works great :thumbsup: .

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. Obviously there may be cases where a cable will need to be used instead (or Dropcheck's SIO-AUX expander board if she still makes that ;) ).

 

BTW, it works great :thumbsup: .

I have those available as well (Dropcheck receives a small portion of the sales as a royalty).

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We have liftoff of another 1088XEL. Forgive the crappy B&W photos - I am putting a PAL signal into my NTSC 1084S via composite.

attachicon.gif20170530_101428.jpg

 

i am currently building one and understand the timing issues from USA vs Europe. I was at sea on a westpac and bought a vhs player and the clock lost ten minutes per hour.

OTAY! I get that.. but can i have a PAL system in the USA?

Without setting up a variable frequency drive?

Douglas

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I'll offer a service for swapping out right angle headers for the PROPER connectors if nothing comes from asking Lotharek to make the boards the way Candle intended them.

 

dont try to desolder yourself.. i lost three pads and that was on the smaller header.

 

Douglas

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dont try to desolder yourself.. i lost three pads and that was on the smaller header.

 

Douglas

The trick is trimming off all of the connectors, then adding solder to each and THEN sucking it off. I have done over 30. It takes about an hour.

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Yep 390 ohm is what they both should be... I'll change it.

 

As for paying me... not something I'm worried about to tell you the truth. Maybe I'll get you to convert a couple of U1MB's over to straight headers for me ;)

 

BTW, I was at the post office today, and I saw that they have what they call a Medium Flat Rate Box that costs about $13 no matter what the weight. It's pretty close to the same size as the box you used, just a bit wider and not quite as tall. that'll be the one I'm going to use to send your board back to you (delivers in 3 days or less). When you use your own box, they'll charge you more every time, best to stick with their own boxes when doing Priority mailing. Something to file away in the brain for future reference.

 

- Michael

 

well i have found that 390 ohm resisters dont exist. couldnt find them anywhere!

Douglas

 

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Hi,

 

I nearly finished my 1088XEL.

Board soldering is complete, only waiting for Bryans UAV and the CVBS/S-Video header to arrive (takes a while from the US to Europe...)

 

Is there any recommended test procedure?

I like to avoid burning things...

 

what I did up to now is:

1) leave all chips out, power up with 5V -> yellow LED is on ;-) checking correct voltage supply at J1, J3 and LM555 -> OK

2) inserting LM555, connecting power switch and power LED from Realan housing, switching on -> no smell, no smoke :grin: LED on housing is on, green LED on board is on -> OK

3) checking correct voltage supply on all IC sockets and headers -> all correct :thumbsup:

 

Anything else to test?

Or just plugging in all chips, UAV and U1MB and crossing fingers?

attachicon.gifIMG_9334.jpg

 

Cheers

Michael

 

 

you soldered that sram directly to the board? I am not worthy!

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there is a row of three headers for the little guys and the 1088 has only two sockets

??

The 1088 has three female headers:

- 2x15 at the rear of the board

- 2x5 in the middle, and

- 2x10 at the front

 

U1MB fits perfectly

 

Look at the other picture you quoted in your post before - the one, where you commented me soldering the SRAM directly into the board (I was missing the right socket and simply could not wait completing the board)

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there is a row of three headers for the little guys and the 1088 has only two sockets

??

The U1MB has three male headers. Once you replace the two large ones on either end, they all point up off the board. The 1088XEL has three matching female headers for those same pins.

 

The three IC sockets on the on 1088XEL underneath the U1MB mounting space are for PIA and two of the PIC chips as I recall (it’s been 8 months since I finished building mine - look at the pics in my earlier post; I *did* build one and I use it nearly every day so I kinda know what I’m talking about at least a little bit )

Edited by DrVenkman

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No there is not 2x5 in the middle of the 1mb

there are three headers in the middle of the U1MB

a five a four and a two.. side by side

where did the two pin header go?

 

Douglas

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The 1088 has three female headers:

- 2x15 at the rear of the board

- 2x5 in the middle, and

- 2x10 at the front

 

U1MB fits perfectly

 

Look at the other picture you quoted in your post before - the one, where you commented me soldering the SRAM directly into the board (I was missing the right socket and simply could not wait completing the board)

 

good job on the sram but there is a 2 pin header that is missing from the scene.

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Yep 390 ohm is what they both should be... I'll change it.

 

As for paying me... not something I'm worried about to tell you the truth. Maybe I'll get you to convert a couple of U1MB's over to straight headers for me ;)

 

BTW, I was at the post office today, and I saw that they have what they call a Medium Flat Rate Box that costs about $13 no matter what the weight. It's pretty close to the same size as the box you used, just a bit wider and not quite as tall. that'll be the one I'm going to use to send your board back to you (delivers in 3 days or less). When you use your own box, they'll charge you more every time, best to stick with their own boxes when doing Priority mailing. Something to file away in the brain for future reference.

 

- Michael

 

well i have found that 390 ohm resisters dont exist. couldnt find them anywhere!

Douglas

 

 

sorry i think it was the 51 ohm resister for the 1200XL build

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This is a mute point! there are no UAV's available so I am currently building a brick

Slow down, take a deep breath and look at the first photo in my first reply to you. That shows all three female headers that everything on the upside-down U1MB plugs into. I built mine myself and use it every day so I’m not blowing smoke here.

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