Were there two 600XL versions?

[s0s]

I got an Atari 600XL computer. Unfortunately, it has problems. There was a blown capacitor which I replaced tonight, and when I went to connect it to my tube tv, it had really bad interference. Some dumbass who had it before me took the channel select switch off, and soldered a wire connecting the middle position to the right position. I tried both channels 2 and 3 on my tv, and both had extremely bad interference.

 

So then I hit the internet and looked for how to connect it to a monitor, but I found TWO versions of it. One page had pictures connecting a cable right next to the power cable, but on mine that's where the switch was. https://www.instructables.com/Getting-started-with-an-Atari-600XL/

 

Does that mean RF is my only option?

 

 

Edited December 28, 2022 by s0s

[Bee]

How about a picture of the back of your 600XL?

 

Thank you

[s0s]

I should have taken one at first, but I just uploaded one. Thanks

[Beeblebrox]

@s0sA 600XL like you own without a 5pin din connection and with a channel switch in it's place is a North American NTSC model. They didn't come with monitor sockets so you only have RF. All other XL and XE A8's (and the 800) came with din5 sockets alongside their RF options. It's only with the NTSC versions of the 600XL they are without this socket. (So an NTSC version of an 800XL comes with one. Not sure why Atari omitted them on the North American 600XL's)

 

By contrast a PAL based 600XL doesn't have a channel switch and comes with a monitor port as well as the RF. 

 

You can add a din5 monitor port if you are handy with a soldering Iron:

https://www.atarimax.com/freenet/freenet_material/5.8-BitComputersSupportArea/7.TechnicalResourceCenter/showarticle.php?37

 

If you do have the skills it is worth it as just having RF - generally the worst output quality - isn't great. 

 

Funnily enough I have an NTSC 600XL on the way where I'll be converting it to PAL as I am UK based.

 

The more important question is where are you based? I am assuming you are in the States.

 

Do you know about the PAL and NTSC differences, software compatibility, etc?  With your NTSC machine it is meant to be used in the States and won't run a lot of PAL based software that comes from Europe.  (A lot of modern games and demos from Europe only run on PAL machines. Some can detect if PAL or NTSC and run. Colour pallets for both are different from one another also.) 

 

More info here about NTSC and PAL. 

https://en.wikipedia.org/wiki/PAL

 

PAL machines have different crystals, extra video circuit componentry and use dedicated PAL Antic and GTIA chips given the different timings involved compared with NTSC. 

Edited December 28, 2022 by Beeblebrox

[s0s]

@Beeblebrox Thank you for that awesome info! I'm aware of PAL/NTSC and pretty good with a soldering iron. I think I have all those. I'm not nearly as knowledgeable with analog as I am with digital electronics. Does it have to be a 2N2222 transistor, or will other transistors work? Just asking because I have several different types stored somewhere, and I'm not immediately sure if I have that exact type. Also, I don't have the large DIN connector. I have plenty of female PS/2 connectors, though. I bought several of them back around 2018 when I made an 8088-based homebrew computer because I planned on making more of them, but never did. Can I just use one of them and make my own cable? Or do you recommend buying one?

Edited December 28, 2022 by s0s

[Beeblebrox]

No worries. I am assuming therefore for are in the US and sticking to NTSC? If so then just follow those instructions. I'd stick to the component spec for the transistor it details and also just buy a din5 connector which has the same footprint as the board mount vias. Then you just remove the channel switch. I'd personally not be going down the ps/2 socket route. You'll likely have to affix it to the casing or mod the pcb. Would look odd. 

 

Once you have the Din5 in place I am not sure if - having removed the channel switch, the rf will work. 

 

Also you will then be able to use an a/v composite cable (din5 to composite), but not S-video straight away. If you want to use S-video you have to addionally connect the chroma signal on the pcb. 

 

 

 

 

 

 

[_The Doctor__]

transistor should be low noise darlington or better transistors. check myteks write up on it.

[+x=usr(1536)]

3 hours ago, Beeblebrox said:

Once you have the Din5 in place I am not sure if - having removed the channel switch, the rf will work.

RF should continue to work with the channel select switch removed, but the modulator will only output on one channel (3, IIRC).

[+mytek]

A 2N3904 will usually substitute fine for a 2N2222, or vice versa. This is the same transistor Atari used on most of its machines for the NPN transistor in many of the video and audio circuits. There really isn't anything critical that requires a specific NPN type in this usage, so a general purpose NPN should do the trick. The main difference between a 2N2222 and a 2N3904 is that the 2N2222 can handle more power, which is not an issue in this case. A Darlington which can handle even more power is not required.

[_The Doctor__]

some other threads report minor success using 2N3904 and MPSA55  hoping for the best results here though

Edited December 28, 2022 by _The Doctor__

[+hloberg]

if it helps, here's where I installed a UAV board in my NTSC 600XL.

also here if you want to 64k cheap.

 

[+bf2k+]

I put a UAV + monitor port in my NTSC 600XL... works great!

[+Stephen]

Don't forget - there is also https://ataribits.weebly.com/ugv.html

[leech]

9 hours ago, Beeblebrox said:

A 600XL like you own without a 5pin din connection and with a channel switch in it's place is a North American NTSC model. They didn't come with monitor sockets so you only have RF. All other XL and XE A8's (and the 800) came with din5 sockets alongside their RF options. It's only with the NTSC versions of the 600XL they are without this socket. (So an NTSC version of an 800XL comes with one. Not sure why Atari omitted them on the North American 600XL's)

Same question could be asked why Atari failed to connect one wire for the 800XL to support S-Video.  I bought a 600xl for dirt cheap many decades ago, but never really used it, and then recently I went to verify it even worked, and discovered the lack of monitor port... such a weird omission since all of the 8bit machines have one (except I think the 400 and 600xl (but only NTSC version)).  Wonder how much they saved for omitting it.  Then again with how much RF shielding the 400/800 required, I'm surprised they didn't try to cheat like Apple did, and just sell the RF modulator as an add-on...

[+hloberg]

1 hour ago, leech said:

....  Wonder how much they saved for omitting it.  Then again with how much RF shielding the 400/800 required, I'm surprised they didn't try to cheat like Apple did, and just sell the RF modulator as an add-on...

the NTSC board has a place for what looks like the monitor circuitry where I believe is used on the PAL boards. (see boxed area where most of the empty board area for monitor circuitry can be seen. -from my UAV mentioned above-) So i can't think saved too much but maybe a few dollars in 1980 money. The PAL didn't have the ch3-4 switch so I guess when they added that switch they just ran out of back plane real-estate to put an monitor port. 

as for why they didn't just add an external RF like AppleII or TI, they have to had a major redesign as they would had to somehow supply power to the RF box which the Atari monitor port didn't supply. 

[leech]

1 hour ago, hloberg said:

the NTSC board has a place for what looks like the monitor circuitry where I believe is used on the PAL boards. (see boxed area where most of the empty board area for monitor circuitry can be seen. -from my UAV mentioned above-) So i can't think saved too much but maybe a few dollars in 1980 money. The PAL didn't have the ch3-4 switch so I guess when they added that switch they just ran out of back plane real-estate to put an monitor port. 

as for why they didn't just add an external RF like AppleII or TI, they have to had a major redesign as they would had to somehow supply power to the RF box which the Atari monitor port didn't supply. 

Yeah I am referring to the 400/800 design.  Watched a video about that, they really wanted something that would connect to a TV out of the box, and the FCC regulations required tons of shielding.  Apple got around this by having an add-in card.  The 800/400 architecture could have been very different...

[+hloberg]

20 minutes ago, leech said:

Yeah I am referring to the 400/800 design.  Watched a video about that, they really wanted something that would connect to a TV out of the box, and the FCC regulations required tons of shielding.  Apple got around this by having an add-in card.  The 800/400 architecture could have been very different...

the TI99 had an external RF box that attached to the monitor port. One of the pins supplied power for the RF box. Personal experience, the box was too heavy and always breaking the leads. otherwise it worked well enough.

[leech]

17 minutes ago, hloberg said:

the TI99 had an external RF box that attached to the monitor port. One of the pins supplied power for the RF box. Personal experience, the box was too heavy and always breaking the leads. otherwise it worked well enough.

Ha, as opposed to the 5200 which has the power supplied to the RF box, which then goes to the console.  Watching that spark if you hook them up in the wrong order is 'fun'.

[BillC]

There were multiple manufacturers of the 600XL PCB, and each could have had more than one PCB version. I believe all versions could be NTSC or PAL depending on the components installed.

There were some 600XL PCB versions that had 2 jumpers which allowed replacing the internal 2364 BASIC ROM with a 2764 EPROM, although the socket also needed extension/replacement to the 28-pin footprint.

Edited December 28, 2022 by BillC

[adam242]

6 hours ago, hloberg said:

the NTSC board has a place for what looks like the monitor circuitry where I believe is used on the PAL boards. (see boxed area where most of the empty board area for monitor circuitry can be seen. -from my UAV mentioned above-) So i can't think saved too much but maybe a few dollars in 1980 money. The PAL didn't have the ch3-4 switch so I guess when they added that switch they just ran out of back plane real-estate to put an monitor port. 

as for why they didn't just add an external RF like AppleII or TI, they have to had a major redesign as they would had to somehow supply power to the RF box which the Atari monitor port didn't supply. 

 

Populating the blank spots on an NTSC 600XL for composite is not difficult or expensive.. the hardest part for me was cutting a clean, round hole in the case for the DIN connector!