hawk

@kbr I'm assuming that you're aware of this guy's work with MCUFriend TFT panels and Arduinos. https://github.com/prenticedavid/MCUFRIEND_kbv/blob/master/extras/mcufriend_how_to.txt I wouldn't go a look there if I were you...it will scare you the number of variants he has identified. This seems like good info though... BTW, what platform do you develop SDrive-Max firmware on? I can build easily on OS X, however on windows, when I used WinAVR, I got compilation errors associated with PGM_P. When I went to AVR Studio 6.? I got it to compile, but haven't yet tested the new binary.

This screen doesn't work with the current software. (1.2b) It displays correctly (You can see the sticker for 8347 on the bottom), however the touchscreen does not function correctly. With one of the builds it was detected by the software, however the touches were not where they were supposed to be. I think I worked out that the touches were rotated 90 degrees, indicating that the X and Y inputs were swapped. Based on this, I guess it should be an easy fix. Back then I was not able to compile my own firmware. Maybe I'll give it another go. These screens are a lot cheaper than the 2.8" ones...about 1/3 the price. ($6AUS).

I compiled my own binaries. I haven't been able to do this easily in Windows (I get compilation errors) but it compiled on OS X using CrossPack for AVR.

Yippee...It works. My cheap 2.8" ID:4747 TFT works. I looked at the changes and they looked pretty much the same as what I tried. The cheap 2.4" MCUFriend TFT that also has ID:4747 didn't work. It displayed correctly but the touchscreen didn't detect. I have a suspicion that the touchscreen interfaces the same as one of the other models, but the orientation is 90 degrees out, not 180. Now I just have to wire up the rest of the SDrive-Max...

Hey NISMOPC, I am in the same situation. I have purchased a cheap 2.8" screen that has TFT ID:4747 that I figure is also a HX8347-D. When I loaded the HX8347-G firmware, the display was correct, but the touch screen didn't work. When I loaded the HX8347-I firmware, the touchscreen worked, but the display was mirrored horizontally. These results led me to believe that it was possible to get this display working, so I built my own firmware version for HX8347-D, choosing the -I display options and the -G touchscreen options. I didn't work. It functioned the same as the -G version. I can't find the options for the display that differ between the -I and -G versions. Any help would be appreciated. Hawk

I like the layout that you're coming up with. I also like the idea of using Kailh Cherry ML-type keyboard switches. Have you considered 3D printed frame (including mount) and a dual colour laser cut insert? The insert could be a thin as 0.8mm. Not really what you'd want to do for mass-production but might work for a few keyboards.

OK, so a bit of research tells me that the biggest issue to overcome in making your own replacement keyboard is the physical size of the keys. The standard 400 membrane keyboard has spacing on about 15mm centres. Modern keyboards are 18mm keycaps on 19mm centres. I guess that's why aftermarket keyboards had to come up with the alternative layouts. I found that Cherry ML keys switches (~12mm x 12mm) would work for spacing, however you would need modified or custom keycaps, as I was unable to find any miniature keycaps. I guess it would be possible to 3D print keycaps these days. My eeePC 701 has key spacing the same as the 400 and it feels really tiny. Why didn't the 400 ever feel that small. For me, back when it was my only computer, it was the membranes that were yuk. I didn't even notice the key spacing...but then I wasn't trying to touch type either. Hawk

I'd be interested to hear from anyone who has had a go at making their own full-stroke keyboard replacement for the Atari 400. I've tried to get hold of an aftermarket replacement keyboard recently and not been able to find one. What are the issues to be overcome when making your own? Cheers, Hawk

I recently purchased a couple of UAV kits from Bryan, so I thought I'd document my installations. http://atariage.com/forums/gallery/album/2096-uav-installation/ Initially I found it difficult to find installation information, but I soon realised that it was in all the forums, it just wasn't all in the same place. The installation of the UAV mod in the XEGS was extremely easy. The most difficult part was deciding how I wanted to implement the mod, and my decision changed a few times and still is not yet complete. I usually want to keep my machines in mint condition, unless something about them indicates that its not really worth it...maybe a broken case, repaired electronics, or I have more than one machine of a particular type in my collection. In this case, the machine I chose to mod had already been repaired by me. http://atariage.com/forums/topic/258432-xegs-repair/?hl=%2Bhawk+%2Bxegs I had originally planned to remove the 4050 chip when I installed the UAV but realised that if I did that I would lose the RF output. I don't use the RF output if I can help it but I wasn't sure whether I wanted to totally remove it. From the monitor photos you'll see that I went to the trouble of replacing the original LCD driver board with a TV tuner LCD controller board. https://www.ebay.com/itm/LCD-controller-board-Kit-diy-VGA-HDMI-USB-TV-for-LCD-LED-Display-Monitor-Panel/152446068465?hash=item237e7e66f1:g:PlsAAOSwdGFYxLsS that allowed me to use RF in for some of my older machines including my 400. I ended up soldering the socket that came with the UAV kit directly onto the pins of the 4050 chip and then plugging in the daughter board. It almost worked first time, however I hadn't realised that I had to provide a colour input signal to the daughter board. I removed the centre pin of the composite out socket from the motherboard and wired the UAV output directly to that. I also included the extra ground wire. I didn't have any small shielded cables so I used regular hookup wire. You'll see from the photos in the album that there was not a great difference in the compisite signal before and after the mod. To be honest, the image was pretty good to start with. However, the S-video output made a big difference. I'd forgotten that my LCD monitor couldn't handle S-video, so I had to test it out on a CRT TV. I had yet to take photos of the S-video. I am also deciding how to fit the S-video socket on the rear of the XEGS. The socket I was able to buy locally is not the one that I'd prefer so I'm putting off installing that for a little bit longer. I'll update again after I've completed that mod...then it will be on to the 400. The 400 will be delayed until I can receive an Audio mod card from Bryan so that I can also get sound after bypassing the RF.

I would like to know from any of the knowledgeable CoCo owners out this what this mod that I found in a CoCo Model 3 that I acquired is? Any ideas? Thanks, Hawk

I wanted to follow up with the outcome of this repair. Replacing the RAM chips worked fine. I now have another working XEGS. I got it hooked up with a disk drive and an SIO2PC and its great. Maybe I'll look at what other mods I might be able to make to this one. I noticed on this http://atariage.com/forums/topic/258497-xegs-hints-for-repair/ thread mikro was having a similar problem, although his screen appeared differently to mine. I will now go and check out my power supplies to see that they're not causing the problem. Thanks very much for your assistance. Cheers.

Thanks very much for the replies. It gives me hope that I'll be able to get it up and running as soon as the IC sockets arrive. I'm hoping that the speed of the RAM chips isn't super critical, as I'm using some 100nS ICs from an old video card.

I finally got a round 'toit' and started having a go at repairing a non-working XEGS that I bought a few years ago. The two RAM chips were running very hot, so I've started by removing them. While I'm waiting for the new IC sockets to arrive so I can continue the repair, I thought I'd ask what to expect if I turn the machine on without any RAM? Aside from the RAM chips running hot, the other symptom I have is a black screen, and this got me wondering whether the RAM test would run at all if the RAM wasn't installed, and that I've actually got another fault as well that will need new another new chip. Any ideas? Thanks, Hawk.

I'm using rewired NES game pads. I find game pads easier to use in many cases these days. I do remember, in my youth, playing Crossfire on my Atari 400 for so long that I had to wrap a tea-towel around my hand to reduce the pain from the CX-40 joystick digging into my hand.