1088XEL Atari ITX Motherboard DIY Builders Thread

[+Firedawg]

DIN-13 RGB Output Update

 

I received my ST-to-SCART cable today and ran some tests.

 

So to summarize... with this cable the ONLY mod required on the 1088XEL, is to jumper PIN-2 to PIN-9 on the DIN-13 RGB connector.

 

I'll post a picture tomorrow showing the DIN-13 jumper connection, and a shot of what the picture looks like on my Samsung monitor.

 

Question: Is there a noticeable difference between the two signals (NTSC-525 lines & PAL-625 lines) with these 8-bit systems to warrant moving to a PAL system?

 

Mike

[+DrVenkman]

D’oh! Sounds like I definitely got both LED’s in backwards then. Drat! I’ll confirm that tonight with the diode setting on my meter but it looks like that’s the issue there. [emoji4]

 

I’m not looking forward to reversing them tonight. Cleaning out holes in this board isn’t fun. Its extra thickness and internal power/ground planes absorb a lot of heat.

[+mytek]

DrV if the LEDs have been installed backwards, removal can be difficult without overheating and destroying them in the process. I usually just cut them in half, and then individually heat each pin and remove it, afterwards replacing with a new LED. If you don't have replacements, PM me your address and I'll send you some (I buy these in bulk for pennies).

[+mytek]

Question: Is there a noticeable difference between the two signals (NTSC-525 lines & PAL-625 lines) with these 8-bit systems to warrant moving to a PAL system?

 

Mike

 

For me at least, I've been going in the PAL direction so as to obtain compatibility with all of the stuff coming out of Europe (demos, games, and apps) that either don't work correctly under NTSC, and/or don't have NTSC versions. Personally I haven't experienced any real issues concerning running my NTSC stuff under PAL, although this isn't always going to be the case for others (your mileage will vary depending upon what applications you regularly use). With Simius's new Sophia GTIA video boards, going PAL over here in the states is easier than ever, especially where DVI monitors are concerned.

[+mytek]

DIN-13 RGB Connection Final Update

 

Although the Cool-Novelties ST to SCART cable is very well built, it quickly became apparent to me that it does not provide stereo audio, which is no big surprise since the ST never had it. So when I looked at the cable to see if there was a spare wire that could be used for the 2nd audio channel, there wasn't one available (every wire was already assigned). But in a weird way this was a blessing in disguise, since I figured out something that would not only provide it, but would also allow the original VSYNC Mod to be retained so that all SC1224 monitors would still work in addition to SCART.

 

Note: After modifying the ST to SCART cable, I believe it will still work on an ST (no guarantee on this aspect), but you'll only get sound out of one channel on a stereo SCART Monitor.

 

UPDATE (1/25/2018): I just recently discovered that the stereo audio going to the DIN-13 connections got accidentally reversed in the PCB layout from what I originally intended, so what I called the right channel in this mod, is in reality the left channel and vice versa. Good news is this mod does correct that problem, and when connected to a SCART TV with stereo speakers things will be in their proper form so no harm done.

 

So here's the plan. First step is to insure that your 1088XEL board has the following mods to the DIN-13 RGB connector.

 

 

Next remove the covers on both ends of the ST to SCART cable, and perform the following mods to that cable.

 

STEP 1: remove covers

 

STEP 2: relocate purple wire from PIN 12 to PIN 4 on DIN-13 plug (new right channel audio)

 

STEP 3: on SCART connector, strip heat shrink away from resistor and disconnect the purple wire

 

STEP 4: on SCART connector, connect both resistors to the yellow wire

 

STEP 5: on SCART connector, remove audio jumper and connect purple wire for right channel

 

DONE: Replace covers

 

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

 

Schematic

 

 

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

 

Do some set-up

 

Set the monitor's Region to Europe, and language of your choice (UK for English menus).

 

If your monitor is a wide screen type, you'll need to set aspect ratio to 4:3 (unfortunately you'll have to do this every time after the monitor has been powered down).

 

 

These are the picture settings I used on my Samsung 730MW SyncMaster monitor (I also went with the Warm1 setting for color tone which looked good for PAL).

 

 

And here's what the end result looks like

 

 

- Michael

[+mytek]

-- DELETE --

[+DrVenkman]

Good news and bad news tonight.

 

Bad news first - I got the old LEDs out and inspected them visually, once I had bright enough backlighting. Indeed, I had them installed backwards. But somewhat worse news, for the life of me I cannot get the negative (ground) through-holes cleaned out, for either LED. The positive holes, with the vias connected only to the traces, came clean easily. But I think the big ground plane inside that thick board is NOT letting me get enough heat in there to clean out the via. I already lifted one square pad (ugh!) but I've confirmed that the remaining "plug" of solder inside the via still has good ground connection. Bah.

 

But on to the good news. Before I removed the LEDs, I plugged in the board and confirmed I had a good 5VDC showing at the positive side of the yellow "5 VDC" LED. Well, now that I know the correct positive side anyway. So I powered up the board and verified that I now had 5VDC at the green LED as well. Even better, I verified that I have good power at J1, J22, J23 and J24, so ... the board is powered up. Huzzah.

 

More semi-good news. I managed to extract each LED intact, short legs and all, and when I reversed them and finagled them into the clean positive holes and wedged them against the negative plug in the through hole, they work and confirmed my voltage measurements by obligingly lighting up.

 

So now I have a decision, I guess. Do I try to clean out those ground plane holes tomorrow with fresh solder and flux and a larger tip on the iron? Or do I say screw it, mount new LEDs half-assed by cutting the negative leg short and "solder welding" it in place to the existing solder plug in each negative hole? Or just leave off the LEDs entirely? Once I have the board cased I'll end up building one of Michael's status boards for the Realan case anyway so these won't matter as much, I suppose, except cosmetically.

 

Thoughts?

 

(ALSO: I'm already planning to build out my second bare board at some point in the fall probably, funds permitting, and moving over the U1MB and Atari ICs, in all likelihood. So these kinds of lessons are definitely going into my mental notebook! Experience can be painful but discovering how to fail and bounce back is an important part of life.)

[_The Doctor__]

You can clean out the hole by making sure the air temperature and area around the PCB is very warm, go to a closet with a space heater if you have too... use a larger tip on the solder iron let it heat load...flux it all up and you should be able to use a real vacuum desolderer, solder sucker (if your quick), hot air gun(blows it out with hot air), or even a piece of lead from a resister or other item attached to the solder tip to melt thru the solder... and if you real skilled pressure air from your a can or high pressure puff from you own mouth.. kid you not I've done sounded like pop noise as I released the the air from my lips (don't touch the board, solder, or soldering iron silly!)

 

Should not be a big deal

[Kyle22]

I have successfully used a plastic drinking straw to blow molten solder out of holes.

[+mytek]

I have successfully used a plastic drinking straw to blow molten solder out of holes.

 

Yep I've done the same thing . Works better than a solder sucker for me when it comes to stubborn holes. The idea is to use the iron underneath, and the straw on top.

[+DrVenkman]

I have successfully used a plastic drinking straw to blow molten solder out of holes.

 

Holy crap, that's genius. I am (honest to $DEITY) gonna try that tomorrow. I'll mount the board above the table in my PanaVise, heat up the solder from below and then give it a try.

 

(EDIT: I see Michael has seconded this idea. Excellent! Thanks, friends!)

[Kyle22]

I hope it works for you, glad to be helpful.

[flashjazzcat]

What temperature is your iron at Herb? I'm using basically the same handle with bevel tip at c. 380°C for everything.

[+DrVenkman]

Hi Jon - I’m using the “default” temp that my Hakko had preset when it was new for almost everything - 750 F (about 399 C). It’s been a good “do everything” temp for most of that I do. I do swap tips as needed though - I have a large-ish tip for removing RF modulators and other bits with soldered lugs, a medium-small beveled tip (1.2 mm I think) for most work, and a smaller 0.6 mm tip for closer work. On this board, I found the smaller tip to work better soldering pins in the tighter quarters but it wasn’t getting it done last night to melt the solder all the way through the board for the ground pins of the LEDs even with liquid flux.

 

I’m definitely going to try the larger tip and flux tonight. Do you think I should reduce the heat on my iron?

[flashjazzcat]

Cool - I just wondered, since you'd mentioned that the 1088XEL PCB was sinking a lot of heat and impeding solder flow. Definitely don't reduce the heat: I have mine stuck at the same temperature on a permanent basis and it works great with 60/40 solder.

 

I actually had to correct a backwards LED on my XEL-CF a few weeks ago and even that little board didn't present any problems when it came to removing solder. Flux will definitely help. Most of the time I use a tip with a flat 45 degree bevel (not sure what the proper name is), and resting the flat of the tip on the via for a second or two with a spring-loaded solder pump on the other side gets the job done. Anything which doesn't want to cooperate gets coated in flux and wicked clean.

[+DrVenkman]

I think I have two things I’m fighting with right now - my cheap solder sucker is about worn out and I don’t always get a good suction, either due to the barrel loosening or the tip getting worn and not lying perfectly flat. And the second factor, I really do think, is the thicker 4-layer board with all that thermal mass. As I wrote last night, the positive side holes cleaned out easily but the ground-plane negative holes don’t want to come clean even with flux.

 

Anyway, tonight I’m going to try flux and the drinking straw trick Kyle and Michael discussed last night.

 

More importantly though - I’m glad I was able to verify +5VDC at some key points last night without any smoke.

[flashjazzcat]

You could pre-heat the board with hot air if the iron is struggling. I was working on an HP laptop the other week (probably a ten layer PCB or something) and it took ten minutes of hot air at 450 C to get a shorted mosfet off the board.

Edited January 19, 2018 by flashjazzcat

[+DrVenkman]

That’s a good thought. I might resort to that tonight if flux plus blowing through the straw doesn’t work.

 

This morning I ordered a Realan H80 from China. Anyone want to start a poll on how long it takes to get here by standard shipping?

[+Firedawg]

This morning I ordered a Realan H80 from China. Anyone want to start a poll on how long it takes to get here by standard shipping?

DrV it's been over 30 days for me. I hope yours takes a faster boat;-)

[+DrVenkman]

DrV it's been over 30 days for me. I hope yours takes a faster boat;-)

Well, it was $45 on the slow boat (using my new customer $4 coupon) versus almost $80 for 6-10 days. Given how much I’ve already spent, I went cheap.

[+DrVenkman]

More bad news/good news tonight ...

 

First the bad news: the drinking straw trick wouldn't do it. The only drinking straws I have in the house are too wide-mouthed to cover only the ground pin holes, and even trying to pinch the end narrower wasn't cutting it.

 

But the good news: more patient flux + heat + solder sucker eventually got both ground holes clean. Although the pads aren't pretty, I managed to clean the holes without damaging the through-hole via itself or the connection to the ground plane. So when I replacement LEDs arrive, and I solder them in correctly, I should have good lights.

 

Finally, in addition to the Realan case I ordered earlier, I also hit up eBay for parts to build controller cables - of course, as it turns out, I'm getting IDC female connectors, ribbon cable and DB9 joystick jacks with crimp connectors from three different Asian sellers. It's gonna be fun trying to guess when everything shows up, and in what order it all arrives.

[+MacRorie]

More bad news/good news tonight ...

 

First the bad news: the drinking straw trick wouldn't do it. The only drinking straws I have in the house are too wide-mouthed to cover only the ground pin holes, and even trying to pinch the end narrower wasn't cutting it.

 

But the good news: more patient flux + heat + solder sucker eventually got both ground holes clean. Although the pads aren't pretty, I managed to clean the holes without damaging the through-hole via itself or the connection to the ground plane. So when I replacement LEDs arrive, and I solder them in correctly, I should have good lights.

 

Finally, in addition to the Realan case I ordered earlier, I also hit up eBay for parts to build controller cables - of course, as it turns out, I'm getting IDC female connectors, ribbon cable and DB9 joystick jacks with crimp connectors from three different Asian sellers. It's gonna be fun trying to guess when everything shows up, and in what order it all arrives.

 

 

 

Just so you know (maybe you can cancel those orders?) I have a *pair* of cables for the H80 for $3, $5 assembled.

[+DrVenkman]

 

 

 

Just so you know (maybe you can cancel those orders?) I have a *pair* of cables for the H80 for $3, $5 assembled.

 

D'oh! I don't know why I didn't check first. You really *are* becoming a one-stop-1088XEL-shop, Marlin! Too late to cancel my eBay orders, I think. Oh, well.

 

Not to worry though - I will (eventually) also be ordering the Realan case panel indicator and mouse select boards from you as well. And who knows? I might actually build out my second board, now that I've learned my painful lessons on this type of assembly.

[Kyle22]

@DrV. Good to hear you got the holes open.

[_The Doctor__]

oh heck I read my what to do list and it looks like it worked for you but I left out one thing ... sometime I clean out stubborn solder by actually adding new solder and they clearing it out.... I don't know if it works because of a change in the solder on the board mixing with the pcb material or pre tinned leads on some components today, all I know is it changes the metallurgy enough to clear it right out... that 60/40 thing again...