800XL screen background color

[c1ph3rpunk]

Have an 800XL that I picked up that wasn’t working so I ordered RAM, GTIA and ANTIC chips to see if one of them remedied the issue. Put in the new memory chips and it immediately came up to BASIC, so I know what that issue was. I’m completely new to the Atari world and was wondering: what color should that screen background be?

 

The reason I ask is this, I wanted to check the GTIA and ANTIC chips I purchased to see if they were actually working, however the GTIA I received produces a different background color than the one that came with. The original chip background is green, the replacement one is black. I went back to look at the original listing for the 800 and it didn’t state NTSC or PAL, I’m not sure which is it and haven’t found reliable ways to determine that. At least, my guess is it’s an NTSC vs PAL difference, maybe. Both chips have the same part number, C014805, the original one is -31, the new one is -01, perhaps that’s it though they’re different manufacturers.

 

Ideas and pointers most appreciated.

[reifsnyderb]

Hello,

 

It should be a medium blue screen with a black border around the edges.  The text should be white.  If the colors are off, the first thing I'd try is to adjust the color pot.

 

Another question is:  How is your 800XL connected?  If it's through the RF connection, you should have all colors.  If it's an unmodified 800XL, and you are using the monitor connection, the colors will be off and the picture will probably look horrible.  Before I added the chroma fix, to the monitor port, the screen was grey with a hint of blue and rather fuzzy.

 

Looking at your part number, it appears that you have an NTSC chip.  So, I guess you have an NTSC computer.  PAL computers have a sort of blue with a slight hint of green look.

 

There is a picture of what your screen should look like here:  http://www.atarimania.com/utility-atari-400-800-xl-xe-basic_13284.html

 

Best Regards,

 

Brian

 

[c1ph3rpunk]

Composite out at the moment, haven’t done the chroma mod but am researching that one. Sounds like that’s next up for me.
 

Didn’t know a color pot existed, thanks, one more to read up on.

[reifsnyderb]

1 minute ago, c1ph3rpunk said:

Composite out at the moment, haven’t done the chroma mod but am researching that one. Sounds like that’s next up for me.
 

Didn’t know a color pot existed, thanks, one more to read up on.

Here's a thread on how to adjust the color with the color pot.

 

https://forums.atariage.com/topic/230435-color-pot-adjustments-for-ntsc-atari-computers/

 

On an 800XL, you should find a hole in the bottom front left corner.  The hole is probably a 1/4" in diameter.  Looking through the hole is an adjustment.

 

Composite out should show color.

 

 

[c1ph3rpunk]

PAC-MAN looks pretty decent when it runs, there’s color, I just can’t remember what colors things are supposed to be. 🙂

 

Thanks for the post link.

[Beeblebrox]

Post some pics of the screens. 

Always worth telling us where you are based.

 

Also, can you snap a pic of your 800xl's motherboard so we can determine if this is a stock 800xl or an 800xlf. (latter with Freddie chip).  Xlf's already have chroma connected as it were. Chroma and luma lines allow use of the superior quality svideo. (composite combines these and results in an inferior output, bled colours, atefacting, blurryness. (Although worth noting for some hi res mode ntsc games artefacting is used to create colours, (Ultima games for example)).

 

If a stock 800xl and you hook up a din5 to svideo cable you would get a black and white image.

Chroma mod is dead easy.  (100ohm resistor in a wire hooking up to the Chroma pin on the Din5 jack to a chroma signal point on the pcb). I'll link to it later. 

 

Bare in mind also if you have an NTSC computer and run pal specific games on it, such as Henry's house, if they do run and don't crash, the colours will be off. Ntsc and pal pallates are different. As you probably know also pal. Is 50hz, ntsc is 60hz

 

 

 

 

 

Edited October 29, 2023 by Beeblebrox
Adding extra info

[c1ph3rpunk]

US based.

 

Last I dug around I don’t believe it’s the XLF.

 

[Beeblebrox]

36 minutes ago, c1ph3rpunk said:

US based.

 

Last I dug around I don’t believe it’s the XLF.

 

Cool. Yup, ntsc machine. Good news also is that you have socketed ram (good Samsung brand), and most 40pin atari chips are socketed.

 

Pity you are missing the cart bay plastic guide. Makes it harder to plug carts in once machine is closed up. You can get 3d printed ones. 

 

Fyi here is the Chroma hookup instruction. 

 

https://forums.atariage.com/topic/352274-best-video-output-option-for-an-800xl/?do=findComment&comment=5269990

 

Edit: colour pot is r38. 

 

 

 

Also ntsc ready screen colour should be this, (random image taken from internet). 

 

Edited October 29, 2023 by Beeblebrox

[TZJB]

12 hours ago, c1ph3rpunk said:

US based.

 

Last I dug around I don’t believe it’s the XLF.

 

 

You are correct. There is no Freddie chip, so it is a standard NTSC 800XL machine. A 800XLF will have the designation on the reverse of the board also.

[c1ph3rpunk]

13 hours ago, Beeblebrox said:

Cool. Yup, ntsc machine. Good news also is that you have socketed ram (good Samsung brand), and most 40pin atari chips are socketed.

 

Pity you are missing the cart bay plastic guide. Makes it harder to plug carts in once machine is closed up. You can get 3d printed ones. 

 

Fyi here is the Chroma hookup instruction. 

 

https://forums.atariage.com/topic/352274-best-video-output-option-for-an-800xl/?do=findComment&comment=5269990

 

Edit: colour pot is r38. 

 

 

 

Also ntsc ready screen colour should be this, (random image taken from internet). 

 

That’s the replacement RAM I picked up, seems to be good quality and works well, 25 chips for like $25. The original ones were one of the brands I’ve read are sort of infamous for failure, uF, uA or something. 2 of them were definitely bad, at least 1 more was suspect when I had the scope on them.

 

I picked up a cart bay guide at VCF-MW from someone, just have to park it in there but it’s good to know there’s an STL around for them. Should probably just print a couple to have around, thanks, wouldn’t even have thought of that.

 

I made up some SALT boards, need to find a ROM chips and flash so I’ll have some around and working.

 

I think the chroma mod is next up for me after the SALT board.

[Beeblebrox]

1 minute ago, c1ph3rpunk said:

That’s the replacement RAM I picked up, seems to be good quality and works well, 25 chips for like $25. The original ones were one of the brands I’ve read are sort of infamous for failure, uF, uA or something. 2 of them were definitely bad, at least 1 more was suspect when I had the scope on them.

 

I picked up a cart bay guide at VCF-MW from someone, just have to park it in there but it’s good to know there’s an STL around for them. Should probably just print a couple to have around, thanks, wouldn’t even have thought of that.

 

I made up some SALT boards, need to find a ROM chips and flash so I’ll have some around and working.

 

I think the chroma mod is next up for me after the SALT board.

Great. Yes you probably had mt ram then. 

 

Cart guide - glad you have one. The stl for a guide I have somewhere. I'll link you to it a little later if I find it. 

 

OS Rom chip wise I've loads of them. Pity I am in the UK.

 

Salt carts are cheap but tf_hh's sys check II is far superior although only sold direct from Germany. They also give you 512k ram.