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1088XEL Atari ITX Motherboard DIY Builders Thread

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OK, I'm getting ready to order the last piece for my 1088, the Ultimate 1MB Upgrade from Lotharek. Just to make certain, before I complete my order? Is there anything else I need from Lotharek for my 1088? There doesn't seem to be any special version for the 1088 or anything. I just want to make certain I don't need any sort of headers or connectors from Lotharek before I complete my order; that I can complete my 1088 with just the Upgrade itself and everything else from the bill of materials.

 

Thanks.

 

Lotharek currently sells U1MB boards with the "correct" male IDC box headers. These will plug down into the female headers on the 1088XEL board just fine. A year ago-plus when the first builders were making these, we had to buy the box headers separately and then perform surgery on the U1MB to replace the 90 degree male in headers Lotharek was using. THIS IS NO LONGER NECESSARY! :)

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Lotharek currently sells U1MB boards with the "correct" male IDC box headers. These will plug down into the female headers on the 1088XEL board just fine. A year ago-plus when the first builders were making these, we had to buy the box headers separately and then perform surgery on the U1MB to replace the 90 degree male in headers Lotharek was using. THIS IS NO LONGER NECESSARY! :)

 

OK, so nothing else to order or do then, except order the Ultimate 1MB Upgrade. Gotcha. Thanks DrVenkman!

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Woo hoo!

 

I've received a couple of smaller component orders the past couple of days. I received my bigger order from MacRorie's Brewing Academy today and I should receive my big Digi-Key order tomorrow. I still have a couple of components and my Realan H60 case on the slow boat from China and the Ultimate 1MB Upgrade coming from Lotharek in Poland, but by this weekend I should have more than enough to get started. It's been years since I've soldered more than just a few things and I've never done anything on this scale, but I'm pretty psyched. I think I'll be an old pro by the time I get the baby done!

 

Here's hoping everything goes well and she powers up without a hitch the very first time.

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Just wanted to share with mytek the video I discovered today about the VCF East 2019.


Joe Decuir is holding a 1088XEL in his hand.

The 1088XEL has no case but I guess this is the way Joe likes to see and touch hardware...

Great acknowledgement for the work done by mytek.

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Hi,

 

I found a little "issue" with the 1088XEL V1.1 - only with PAL chips and crystal equipped (I think so).

 

After building 7 pieces of the 1088XEL V1.1 for different people, I have every time the opinion, that the screen is too greenish. Look here, one example:

 

PAL_Ready_Screen.thumb.jpg.6a5f71c9a6b92fb13a7d9487d838a4ae.jpg

 

Of course I know, effects like camera setup, color settings at your computer or mobile device is always falsifying what I want to show, but I think most people trust me to judge this behavior the right way 😀

 

One of 7 boards I have assembled didn´t make any right color, it´s shows totally wrong colors even when I set the color pot to the maximum. So I start to examine this issue and found out, that the maximum voltage which can be produced by the loading pump at the 1088XEL circuit is approx  6.5 volts. Some of the 7 pieces only reach 6.0 volts, one only 5.9 volts.

 

As every hardware guy knows, the color settings depends on GTIA, CPU (which PH1 signal is used for the loading pump) and in part also ANTIC. So I try to change them with several other, best known working parts and the issue changes slightly, but never the wrong color behavior is solved.

 

After changing several GTIAs and CPUs, I look about the differences between Mytek´s solution and the one found in the 800XL five-chip standard version. The one and only difference is the transistor Q9. Atari used the 2N3904 transistor nearly everywhere, Mytek uses the 2N2222. So I change the following transistor to a 2N3904:

 

1088XEL_Video.thumb.png.a84dc73a30259302b0eb93af434102a9.png

 

This fixes the behavior perfect. Now the range of voltage setting with the color pot is up to 8.5 volts, which matches my reference 800XL. I didn´t look closer into the datasheets of the transistors, but the 2N3904 works better here. Maybe it´s also my 2N2222 series I purchased, but generally all parts of the 1088XEL I have assembled work fine.

 

@Michael: Would suggest you to mention that in the BOM. I can´t test now, if NTSC is also affected, but I think not, as most systems are build from NTSC using guys IMHO.

 

Jurgen

 

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Here is my 1088XEL, PAL Crystal and Chips. VBXE, SVideo, Composite. All out of the same monitor. The VBXE is going through a GBS8220 the SVIDEO/Composite are going through an Ambery video to VGA converter 

 

IMG_1914.jpegIMG_1916.jpeg

Composite

 

 

If anything I think it's a little too blue, I probably need to tweak the pot a bit.

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Just to chime in here on this topic:

 

1. Glad the 3904 fixed it for you, tf_hh

2. My personal daily driver XEL is a PAL unit and it does not suffer from color radiation problems at all.

3. I have built five PAL 1088XELs for customers and have not had the color problem you speak of.

 

Perhaps, there is something to be said about 50Hz power versus 60Hz power? That is the only difference I can think of.

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On 5/14/2019 at 9:45 AM, DrVenkman said:

 

Lotharek currently sells U1MB boards with the "correct" male IDC box headers. These will plug down into the female headers on the 1088XEL board just fine. A year ago-plus when the first builders were making these, we had to buy the box headers separately and then perform surgery on the U1MB to replace the 90 degree male in headers Lotharek was using. THIS IS NO LONGER NECESSARY! :)

GREAT... I ordered mine a while ago.. just tonight tried unsoldering one of the headers.. I lifted 2 pads.. from the solder side.. but it looks like I might have lucked out and nothing is connected to those pads on that side of the board.

 

The U1MB is just a 2 layer board correct??   Now in my kit from McRorie, I got 2 LONG female headers.. and a bunch of single row pins.. These are for this job correct???  How do I cut the headers?? 

 

James

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The tall headers are for the main board. I cut mine with a Dremel. Taped off the area, then cut off the short part. I left enough buffer to let me solder the cut edges smooth. Unfortunately I didn’t take any pics of the U1MB pin installation. However, I used dual-row male pin headers, not the single-row versions you have in your photo.

 

I would suggest that you don’t solder either the tall headers or the pins to the U1MB until you have everything lined up. Tack one pin on a corner of each connector, ensure everything is lined up straight and correctly, then do the rest of the pins.

 

 

82A6855B-A5B8-42D6-861A-8CF3EDCE169A.jpeg

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Here's the video I already shared with @Bikerbob, just in case posting it here boosts the view count helps anyone else:

 

 

Edited by flashjazzcat
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Ok, couple of back and forths with Lotherak, and I know how to salvage the pad I pulled.. VERY lucky for me P5 pin5 is not used.. pin7 goes to A8.. and a simple jumper from the backside of the board will fix that up. 

 

I will follow Jon on the pin removal.. damit damit damit.. I have a powered solder sucker.. and got too confident.. so easy to remove the individual pins.. THATS what I should have done. 

 

McRorie, assuming you read this.. I assume those individual pin rows are what were included to make the header??  (OR anyone else who did it?)

 

Bought all the kit in 2017 - just doing it now..    OH - recomendation on Solder paste.. I saw you using something in a syringe Jon.. I have a small tub of paste.. good enough? or should I get that stuff?

 

James

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49 minutes ago, Bikerbob said:

I assume those individual pin rows are what were included to make the header

I only use two single row headers side-by-side as a dual row headers in desperate circumstances (i.e. when I ran out of dual-row strips). :)

50 minutes ago, Bikerbob said:

I saw you using something in a syringe Jon

I'm not sure what flux I was using back then, but now I won't use anything other than AMTECH NC-559 flux. Miles better than anything else I've used, recommended by Louis Rossmann, available from his online shop if you want a reliable source, and coupled with 1.5mm Goot Wick (which I think Louis also sells), makes desoldering a cinch.

 

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7 hours ago, Bikerbob said:

Ok, couple of back and forths with Lotherak, and I know how to salvage the pad I pulled.. VERY lucky for me P5 pin5 is not used.. pin7 goes to A8.. and a simple jumper from the backside of the board will fix that up. 

 

I will follow Jon on the pin removal.. damit damit damit.. I have a powered solder sucker.. and got too confident.. so easy to remove the individual pins.. THATS what I should have done. 

 

McRorie, assuming you read this.. I assume those individual pin rows are what were included to make the header??  (OR anyone else who did it?)

 

Bought all the kit in 2017 - just doing it now..    OH - recomendation on Solder paste.. I saw you using something in a syringe Jon.. I have a small tub of paste.. good enough? or should I get that stuff?

 

James

 

I have pulled a pin out of the board once, so I sympathize.  After doing it once, you get REAL careful after that.

 

I use the single-row all of the time without problem.  The trick is, as has been said, is to not solder them in until you can have them seated in the connectors on the motherboard.  I find it easier (and less expensive) to have a large supply of the single-row.  However, if I had a large supply of the dual row, I would use those, I suppose.  Just a matter of what is on hand.  EDIT:  Single-row is also what the BOM called for. Re-EDIT: To be precise, the BOM does not call for either. However, at the time, we were not using dual-row headers for anything.

 

Solder paste?  I only use solder paste for SMD work.  I use this: "MG Chemicals 60/40 No Clean Leaded Solder, 0.032" Diameter" for all of my assembly work.  I go through about a 1# spool a month.

 

Hope this helps!

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10 hours ago, Bikerbob said:

GREAT... I ordered mine a while ago.. just tonight tried unsoldering one of the headers.. I lifted 2 pads.. from the solder side.. but it looks like I might have lucked out and nothing is connected to those pads on that side of the board.

 

The U1MB is just a 2 layer board correct??   Now in my kit from McRorie, I got 2 LONG female headers.. and a bunch of single row pins.. These are for this job correct???  How do I cut the headers?? 

 

James

 

You need to trim those down to size.  I use some snips to get it within one pin and then dremel it smooth.

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On 6/30/2019 at 9:09 AM, tf_hh said:

After changing several GTIAs and CPUs, I look about the differences between Mytek´s solution and the one found in the 800XL five-chip standard version. The one and only difference is the transistor Q9. Atari used the 2N3904 transistor nearly everywhere, Mytek uses the 2N2222. So I change the following transistor to a 2N3904:

 

1088XEL_Video.thumb.png.a84dc73a30259302b0eb93af434102a9.png

 

This fixes the behavior perfect. Now the range of voltage setting with the color pot is up to 8.5 volts, which matches my reference 800XL. I didn´t look closer into the datasheets of the transistors, but the 2N3904 works better here. Maybe it´s also my 2N2222 series I purchased, but generally all parts of the 1088XEL I have assembled work fine.

 

@Michael: Would suggest you to mention that in the BOM. I can´t test now, if NTSC is also affected, but I think not, as most systems are build from NTSC using guys IMHO.

I forgot to look into this when you first posted, and after a few days it left my brain to do so. I'll check it today and see what voltage I see on my XELs.

 

 

2 hours ago, MacRorie said:

I use the single-row all of the time without problem.  The trick is, as has been said, is to not solder them in until you can have them seated in the connectors on the motherboard.  I find it easier (and less expensive) to have a large supply of the single-row.  However, if I had a large supply of the dual row, I would use those, I suppose.  Just a matter of what is on hand.  EDIT:  Single-row is also what the BOM called for.

If that's true (which I don't doubt) that was a mistake on my part. It really should have been speced as a dual row header.

 

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10 minutes ago, mytek said:

 

If that's true (which I don't doubt) that was a mistake on my part. It really should have been speced as a dual row header.

 

To be precise (and I edited my post, above), the BOM did not call for either.  However, at the time, were not using dual row headers for anything and, when we were using dual rows, the BOM called for single-row doubled up.

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Pragmatically, it should be neither dual row nor single row open header strips. Ideally it should be an enclosed IDC header as shown at the end of my video. That's what the original U1MB shipped with, it's what Lotharek has now reverted to, and it's what's on the U1MB board in my 1088XEL.

 

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Just now, flashjazzcat said:

Pragmatically, it should be neither dual row nor single row open header strips. Ideally it should be an enclosed IDC header as shown at the end of my video. That's what the original U1MB shipped with, it's what Lotharek has now reverted to, and it's what's on the U1MB board in my 1088XEL.

 

That's a good call.  It's a moot point now since all U1M are shipped with the shrouded headers. 

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I agree that it's a moot point since the U1MB now ships with vertical headers, but just out of curiosity I checked the BOM on the Ataribits site dated May 10th 2018 and the only reference I see to the U1MB doesn’t spec anything other than the tall dual row headers that go on the XEL motherboard.

 

1088XEL_BOM_U1MB.thumb.png.23c5faffe29ecb221a45f31b382bdee5.png

 

Perhaps there is another maybe earlier BOM floating around that says otherwise?? No matter, case closed ;-) .

 

BTW, as far as the XEL and XLD is concerned much nicer to have unshrouded headers on the U1MB side. The shroud although great for insuring ribbon connectors mate correctly, does just the opposite when it comes to plugging into female board headers. Since it obscures your view, its very easy to be off by one pin either way when mating the U1MB with an XEL or XLD motherboard.

 

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2 minutes ago, mytek said:

Since it obscures your view, its very easy to be off by one pin either way when mating the U1MB with an XEL or XLD motherboard

It's not that hard to not misalign it, though, which is fortunate given that all Lotharek boards now have the shrouded headers we advocated for so long.

 

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14 minutes ago, mytek said:

I agree that it's a moot point since the U1MB now ships with vertical headers, but just out of curiosity I checked the BOM on the Ataribits site dated May 10th 2018 and the only reference I see to the U1MB doesn’t spec anything other than the tall dual row headers that go on the XEL motherboard.

 

1088XEL_BOM_U1MB.thumb.png.23c5faffe29ecb221a45f31b382bdee5.png

 

Perhaps there is another maybe earlier BOM floating around that says otherwise?? No matter, case closed ;-) .

 

 

Correct, as I said, the only thing listed in that BOM were the single pin male connectors.  The female connectors you reference above, were definitely dual row and needed to be cut and sanded.  The hints used to have a notation (might even still have it) that it would be best if you put everything together (U1M+male headers+female headers+motherboard) before soldering those parts.

 

12 minutes ago, flashjazzcat said:

It's not that hard to not misalign it, though, which is fortunate given that all Lotharek boards now have the shrouded headers we advocated for so long.

 

FJC, I think MyTek is referring to the fact that since they *are* shrouded, it is easy to mis-align the U1M when attaching it to the motherboard.  If Lotharek put NON-shrouded headers, it would be easier to attach to the motherboard without misaligning it.  However, I will take shrouded headers versus right-angle unshrouded any day of the week!

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3 minutes ago, MacRorie said:

Correct, as I said, the only thing listed in that BOM were the single pin male connectors.  The female connectors you reference above, were definitely dual row and needed to be cut and sanded.  The hints used to have a notation (might even still have it) that it would be best if you put everything together (U1M+male headers+female headers+motherboard) before soldering those parts.

 

FJC, I think MyTek is referring to the fact that since they *are* shrouded, it is easy to mis-align the U1M when attaching it to the motherboard.  If Lotharek put NON-shrouded headers, it would be easier to attach to the motherboard without misaligning it.  However, I will take shrouded headers versus right-angle unshrouded any day of the week!

Yep always plug-in all the female headers into the U1MB, drop the complete assembly into the XEL motherboard, and then solder it up. Perfect alignment each and every time 👍 . This is still covered in the notes on the current BOM.

 

Yes much easier to see that the pins are aligned to the female board headers without a shroud in place. But that is such a minor issue, and I really don't care what male pin header is used on the U1MB so long as it's vertical, because at least now no modifications are required :) .

 

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I think its also worth mentioning, that it would be better to use an un-shrouded header for the MPBI for the same reasons I mentioned about the U1MB pin headers. I know the BOM says otherwise, but that spec was a carry over from when I thought a ribbon cable was going to be used instead of the direct board plug-in we see now with the CF2 and CF3 IDE boards.

 

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