help wanted Are there any disassembly guides?

[TheRaven81]

The short of it is that I need/want a really detailed guide on the disassembly of an Atari 800XL, so that I can hopefully make a small upgrade to it soon. A video would probably be best, but written is OK too so long as it has pictures to show everything. Even better would be if there was possibly someone from this forum that was local to me(Rochester, NY, USA) and be willing to meet and help me directly(after this whole global virus crisis thing is over with, of course. Plus it'd be nice to make a new friend that was nearby and not just through my screen lol). 

 

I got the courage to open it up finally, but I didn't get very far. I got as far as having it opened from removing the 6 bottom screws, flipping it back over, and removing then laying the top half over upside down next to it, still connected. Couldn't figure out how to disconnect the keyboard half without possibly damaging it - the ribbon looked so flimsy. But I needed to get under the RF shield so I didn't think leaving it there would be a problem. But I can't get the shield off without removing the board from the base, and it seems stuck to it. I found 2 screws inside it - one below the DIN for the power, and the other was above the top right corner of the shield. There is supposedly supposed to also be a screw between the controller ports, but I did not see one. I saw a hole for one, but there was no screw in it. So I removed those two that I saw, but it still seemed stuck. Being able to get this up is the only way I am getting the shield off. Because I also saw, that the shield was screwed on from the bottom going up. 

 

I'll continue to look to see what else I can find, but hopefully someone will be able to help me, locally or not.

[jamm]

There are a lot of disassembly videos on YouTube, and at least a few by @flashjazzcat that go into a lot of detail, although they're mostly focused on installing an upgrade.  I found his and a few others I found randomly on YouTube to be very helpful when I was in doubt about how to proceed.

 

The keyboard connector does feel very flimsy, but it'll do fine and survive many dis/reconnections as long as you're reasonably careful with it.  (I say this from childhood experience taking my 800XL apart and putting it back together a good number of times.)

 

Taking the motherboard with the RF shield in place completely out of the case did take more effort than I would've expected, but nothing broke.  I imagine you learn over multiple attempts exactly what angle you have to maneouver things towards to make the removal as easy as possible.

 

Also keep in mind that there were quite a few manufacturing changes and inconsistencies over the years, so the inside of your machine may not be just like those in the videos.  The RF shield on mine was completely screwed together, for example, and didn't use any of the metal twisting tabs I've seen on every 800XL disassembly video.

 

 

 

Edited April 10, 2020 by jamm

[Rybags]

Keyboard fairly easy, there's generally 2 types.  Some have just the plastic ribbon but some have a little circuit board edge connector.

The trick is pinch either end and pull out evenly.  Similar for reinserting, try not to bend it out of shape.

Disassembly is easy, 800XL has the RF shield halves screwed together.  The trickiest part is getting the board in/out of the case.  There's a small screw between the joystick ports and the board has to be maneuvered in/out of the side/back ports to fit properly.

When pulling the metal tabs from around the PBI at the back, remember what order everything goes in.

 

Barely worth doing as a video.  IMO a series of photos and an ifixit.com guide would be way better.  And if you were to do that, may as well include the chroma line addition in the process.

[TheRaven81]

2 hours ago, jamm said:

Also keep in mind that there were quite a few manufacturing changes and inconsistencies over the years, so the inside of your machine may not be just like those in the videos.  The RF shield on mine was completely screwed together, for example, and didn't use any of the metal twisting tabs I've seen on every 800XL disassembly video.

I can take it back apart at least to the point where I had it already, and take some photos. They might help with any specifics for my machine. I'll edit this post once I take them. I think mine is similar to yours, the RF shield seems as if it's only on by screws. But those screws go in coming from the bottom of the board and sticking up. So I can't easily unscrew it unless I get the board out and flip it over.

 

EDIT: here are some pics, not really sure how helpful they are atm, might try to take better ones later

https://imgur.com/a/Y9BhQBW

Edited April 10, 2020 by TheRaven81
added pictures

[jamm]

Looks just like mine (except mine is an Alps keyboard).  Pull out the keyboard connector (slowly but firmly.  You don't have to remove the shielding from the motherboard - just the small number of screws that bolt the motherboard down to the bottom of the case - I forget how many there are - 4 or 5 maybe?

 

The hardest part is pulling the motherboard+shield from the bottom case.  There are two points where it gets stuck, and I just had to put some manual pressure on those points: you have to get it to clear the power switch on the left side and the two joystick ports on the right side.  I think I ended up working on the joystick ports first and then the power, but it's probably no different going the opposite order.

 

Once you've cleared those two sticking points, the motherboard should come right out.  And it's a lot easier putting it back in, although the same two spots will be your focus there, too.

 

[TheRaven81]

the only screws I see holding it down are the 2 near the top. The upgrade I have planned is a replacement of the BASIC chip, which is under the shield. I'm trying to get it off now, before I have the replacement chip, so that I can see where it is, and how it is seated in there. I'm hoping real hard that it's already socketed. Otherwise I may have to decline the idea of doing it. I have literally zero soldering skills, so it's going to need to be a "pull old chip out, put new chip in" deal, or I can't do it.

[bfollowell]

Once you get the two or three screws holding the shield to the case out, you have to completely take the shield/motherboard out of the case, flip it over, and take out the screws from the bottom that are holding the upper and lower half of the shield together.

 

[xrbrevin]

if i remember rightly, it involves 'jiggling'

1. remove the 2x screws and if necessary also the 2x parallel port shield screws

2. lift the front-left side of the motherboard

3. pull it towards you to disengage the power switch from its aperture - you may need to flick the switch to help it clear the case

4. disengage the SIO port from its aperture. start by clearing the top-left side of the port - you will likely need to jiggle the case near the port to get it started

5. disengage the joystick ports from their aperture

 

for reassembly, reverse the above. be careful to avoid getting the motherboard stuck at the rear-right screw hole as there is a small lip that likes to snag and hamper the progress

 

[TheRaven81]

https://imgur.com/a/Y9BhQBW

 

new pictures, in better lighting. I was able to get the board out finally, so there are some pics detailing more of the board, some were mainly for my own reference. Took the shield off, and it looks like ALL the chips are socketed, which is exciting! Took a look underneath, and I don't see any patch wires to the chroma line, so there's no chroma mod done either. That's also something I'd like to look into probably later down the line, when I actually have a monitor/tv with an SVideo input on it. THAT I definitely AM going to have to learn to solder for though. 

 

Oh. A request. Now that I have gotten the top shield off, in the above link there's a pic of all the chips. Would anyone be kind enough to take that picture, and label the chips for me? I looked all over google, and found many pics of the board, but none that were labeled. It would be a big help.

Edited April 10, 2020 by TheRaven81
request added at end

[jamm]

This has some 800XL motherboard pictures with the major chips identified:

http://en.devzine.pl/2019/09/23/how-to-upgrade-your-atari-with-ultimate-1mb-stereo-and-sophia-dvi/

 

 

Edited April 10, 2020 by jamm

[ivop]

When I clicked this topic, I thought it'd be about disassembling 6502 code, not about physical disassembly of the Atari itself

[Mclaneinc]

Same