800XL UAV Install - SVID Screen Missing Every Second Vertical Resolution Line

[YSG2020]

Just installed UAV board in my 800XL rev D board. Using SVID and screen display is missing every second vertical resolution line. What could this issue be indicative of? Thanks. 
 

 

[+DrVenkman]

You've got your composite and chroma lines messed up, I think. 

[YSG2020]

The instructions say something about combining chroma and Luma at the monitor. I’m not sure what option that would be  necessary for? I’ll try reversing those as you mentioned and see what happens. 

[+DrVenkman]

9 minutes ago, YSG2020 said:

The instructions say something about combining chroma and Luma at the monitor. I’m not sure what option that would be  necessary for? 

Have no clue since the UAV also provides a composite signal, as does the standard Atari computer DIN. But I've put in over half a dozen UAVs into various machines and your symptoms are the the sign of something mis-wired. 

[YSG2020]

Here’s how it’s wired at present without having chroma and luma connected. I’m think to run a connecting wire from the Luma connection on the board to the chroma pin on the 5din port... 

 

Edited February 15, 2020 by YSG2020

[flashjazzcat]

You have composite and luma (the two brown wires) mixed up, exactly as per my last video. Probably for the same reason as well.

 

 

Edited February 15, 2020 by flashjazzcat

[YSG2020]

Wow Flassjazzcat, if that is seriously the problem, then it means UAV’s printed instruction installation manual is incorrect, as my connections are exactly per their guidance.

[flashjazzcat]

1 minute ago, YSG2020 said:

UAV’s printed instruction installation manual is incorrect

I've never seen it... I didn't know there was one.

 

[YSG2020]

Yup it’s fixed. Lol. Thankyou! So either the UAV manual is incorrect or the wiring needs swapped for a rev d motherboard in an 800xl. 
 

[+Nezgar]

1 hour ago, flashjazzcat said:

I've never seen it... I didn't know there was one.

I recall @MacRorie was working on a very detailed install manual to include with the UAV's he's producing. I don't think it was released publicly.

[+DrVenkman]

I ordered a UAV a few weeks ago to put into one of my 5200's and got one of Marlin's printed manuals but I didn't pay it much mind - I've installed too many of these things into too many computers (800XL, two 1200XL's, 1088XEL, 1088XLD, 2600, 7800 and now a 5200) to worry about where the composite, chroma and luma and ground connections go to the UAV. Jumper configurations for the computers and 5200, sure, and close attention to where to solder the LUM, SYN and COL wires into the UAV if installing without a terminal block. But those locations are silkscreened onto the bare boards of the Rev D's so it's no trouble at all. Anyway, glad the OP got the issue resolved.

 

As an aside, I discovered something interesting today while moving some connections around on my Incognito 800 and a C1902 monitor: that particular monitor doesn't care one whit whether you feed it a composite or bare chroma signal into the Chroma connection on the monitor; so long as you have Luma connected too, you get a lovely crisp S-video display, utterly indistinguishable from feeding it the proper Composite signal. So in other words, a stock Atari XL without a separate Chroma signal on the jack would've still given you an S-video display! Conversely, if you feed it a Chroma signal into the Composite jack, it won't work at all because you don't have a sync signal on the Chroma line. I need to try this with my C1702 monitor as well. If it works the same, it might do a bit to explain to incredulous modern minds why Atari dropped the separate Chroma signal from XL computers.

[flashjazzcat]

5 minutes ago, DrVenkman said:

But those locations are silkscreened onto the bare boards of the Rev D's

Unfortunately you can't see the silkscreen if the terminal block is already soldered in. I think I installed three or four of the things and - as explained in the video - I keep googling the same AA thread (in the absence of a landing page with a manual) for a quick reminder of the pinout. Not sure if the person who fitted the board featured in the video did the same thing, but it's fairly easy to get mixed up when working from a photo. That's two boards with exact the same installation error in the same week.

[YSG2020]

Yup. It’s because of backwards instructions now printed and distributed in the UAV pkg. I let them know so they can correct or this will keep happening. Lol. Glad it’s fixed. The SVideo out to my SVGA crt monitor looks incredible now. Super sharp and clear. 

[+Nezgar]

4 hours ago, DrVenkman said:

Conversely, if you feed it a Chroma signal into the Composite jack, it won't work at all because you don't have a sync signal on the Chroma line. I need to try this with my C1702 monitor as well. If it works the same, it might do a bit to explain to incredulous modern minds why Atari dropped the separate Chroma signal from XL computers.

My daily driver 800XL has a UAV rev D connected to a 1702 with Luma/Chroma, is a very crisp clean picture.

 

I have a 2nd 800XL I've cleaned up, but still has the stock output with no discrete chroma out, connected to another 1702. I tried using the Luma+Composite input combo to the monitor, and it worked, kind of. It behaved a little odd with the colour saturation changing, or colour completely dissapearing depending on the picture, seemingly more prevalent on primarily bright screens... so I reverted it to composite only as it consistently works, at least until a UAV goes in.

 

I honestly have not tried this combo on the other 1702 to compare if this behaviour is consistent.

[+mytek]

I always use this as my guide.

 

 

Made by Bryan, the creator of the UAV.

 

[Moe]

On 2/15/2020 at 5:13 PM, YSG2020 said:

Yup it’s fixed. Lol. Thankyou! So either the UAV manual is incorrect or the wiring needs swapped for a rev d motherboard in an 800xl. 
 

Thanks!  I had the exact same problem. This fixed it for me.