Converting 130XE PAL to NTSC

[ratwell]

Doing some research on this subject...

130XE NTSC to PAL with replacement of ANTIC chip only:

 

 

800XL NTSC to PAL (new chips, new crystal, adding in PAL circuitry):
 

 

B&C have been selling 130XE PAL units with bad GTIA chips for years but it's not clear to me what's specifically required to perform the upgrade.

 

What are the specific steps to covert a PAL 130XE to NTSC?

 

I found this reference also:

 

https://www.myatari.com/nirdary.html

Edited March 19, 2021 by ratwell

[+ZuluGula]

Where are you located?

[ratwell]

5 minutes ago, ZuluGula said:

Where are you located?

Canada

[+ZuluGula]

It will be easier to trade with someone for NTSC.

[Sugarland]

It's not recommended to convert a PAL machine to NTSC. PAL machines are worth more. That is why you are having a difficult time finding said instructions.

Edited March 19, 2021 by Sugarland

[ratwell]

I found some details here but there thread ends after the 800XL changes:
 

  

On 5/18/2010 at 11:52 PM, Alphasys said:

The copies of the original 600XL and 800XL schematics, have footnotes about the changes between PAL and NTSC models (they call the NTSC "domestic version"). I can't find the 130XE schematic at the moment, but I suspect there's a similar set of footnotes. Just to give an example of the differences:

 

- The color clock assembly from the pal versions (around the 4.433MHz crystal) is completely removed and replaced by a jumper.

- Modulator type UM1662 (C061658) replaced by UM1652 (CA061618)

- Main clock crystal is replaced (from C015510 3.546894MHz to C061090 3.579545MHz)

- Video output circuit between GTIA and modulator around 3 transistors is removed.

- One resistor is added, and one capacitor changes from 100pF to 4.7pF.

 

Notable: There is no mention of replacing the ANTIC/GTIA chip to a different type/part number. This above list is taken from the 600XL schematic. The 800XL footnotes are similar.

 

I'll try to find the 130XE schematic. I should still have one or two copies of it in storage.

 

At least it shows that the differences are all in discreet components, with only a few transistors involved, no integrated circuits are affected.

 

It should therefore be relatively simple to change a PAL machine such that it will produce an NTSC composite signal. Without replacing the modulator, it'll be hard to get an accurate picture on the RF output however, not knowing the differences between these "black box components".

 

 

[ratwell]

I found the 130XE Reference Manual and there seems to be a unified schematic within that highlights the differences between the NTSC (domestic) and PAL (international) versions:
 

 

Edited March 19, 2021 by ratwell

[1200XL M.U.L.E.]

@ratwell Just curious ... what is your motivation for converting from PAL to NTSC?

[ratwell]

I would like to use it with my Sony CRTs without any converter boxes.

[manterola]

So... Is it from Pal or from Ntsc? There is contradictory information in the thread.. or I misunderstood what I read 

[ratwell]

1 hour ago, manterola said:

So... Is it from Pal or from Ntsc? There is contradictory information in the thread.. or I misunderstood what I read 

PAL 130XE converted to NTSC.

 

[manterola]

2 hours ago, ratwell said:

PAL 130XE converted to NTSC.

 

An you are in Canada?. it sounds more convenient to get another 8 bits Atari computer. Probably someone in Atariage (maybe located in Canada) is willing to sell one to you... The PAL computer are more expensive in this side of the world and you can run some cool demos not available for NTSC, so that's why you might reconsider and keep your PAL Atari.

 

[Turbo-Torch]

Best Electronics had brand new NTSC 130XE motherboards (with warranty) for less than what the defective PAL boards were selling for on eBay.  I paid $79, but that was at least 2 years ago.

[1200XL M.U.L.E.]

5 hours ago, ratwell said:

I would like to use it with my Sony CRTs without any converter boxes.

I understand.

 

I would still leave the PAL version alone and get a NTSC machine from eBay. As others have said, leave the PAL version for specific games, apps, and demos that wouldn't run on a NTSC machine. With two machines you would have practically 100% coverage of software compatibility ... past, present, and future. The compromise would be needing a converter box. That's not bad though. A good box will give you very, very clean output.

[ratwell]

Thanks for all the tips!

[ratwell]

On 3/19/2021 at 8:54 PM, Turbo-Torch said:

Best Electronics had brand new NTSC 130XE motherboards (with warranty) for less than what the defective PAL boards were selling for on eBay.  I paid $79, but that was at least 2 years ago.

Prices have indeed gone up:
 

Atari US / NTSC 130XE Populated Motherboard.

CB101089
$139.95