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mytek

600XL upgraded with built-in MIDI, UAV, Basic RevC, and 64K

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Getting ready for the arrival of Dropcheck's XE Super Cart 128 with MidiMaze.

 

For this project I decided to take a stock 16K 600XL that was badly in need of a RAM upgrade, and trick it out with MIDI in mind. To do this, I started with my SIO2MIDI board, after first shaving it down a tiny bit on the sides. This allowed me to drop it into the area where the RF modulator once resided, and would allow the new MIDI jacks to be even with the power and video jacks. I also took the opportunity to add the 64Kx4 RAM chips, and modify the addressing (some bent up IC pins and 3 jumper wires). For the new video jack I used a UAV to give it the best possible picture. And as long as I had this guy cracked open, I also changed out the Basic RevB ROM for a RevC ROM.

 

The following pictorial documents the hardware changes required.

 

Surgery - gotta make room for the SIO2PC, as well as strip out all of the unneeded video components.

Unfortunately some traces get severed on the bottom side that will need to be jumpered.

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Bottom view of 'inserted' SIO2MIDI board, some required wire jumpers to replace missing traces, and all held in place by clear epoxy.

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Upper view showing black epoxy used between MIDI and Video jacks to add strength, UAV & RAM installed.

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SIO connections.

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Overview, all board mods completed.

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Adding new holes in the case for the MIDI and Video jacks.

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Modified board placed back in the case (front view).

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Modified board placed back in the case (rear view).

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Adding MIDI com LED (required a hole in the bottom metal frame of the keyboard)

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Finished look of MIDI com LED installation.

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MIDI com LED activated.

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Finished look of new MIDI and Video jacks + labeling (had to enhance the image to see the new DIN jacks).

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At this point the system is fully operational except for two minor omissions caused by some traces that got cut as part of the modding. That would be Audio-In on both the SIO and the PBI. Since I don't really need those for my intended application, I decided to not run jumper wires to restore them. However if that changes, I can always add them in at a later time.

 

Now I just need my MIDI-MAZE cart, and I can link this up to my MIDI ring and start blasting happy faces :) .

 

 

 

 

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I know your address, I'll be sending my 600XL to you this weekend to upgrade :D

 

I only do one such mod for my entire life. It's one of those "been there, done that" kinda things. but hopefully someone else will pick up where I left off, and make something even cooler :) .

 

Just think... this could have been the 600/800XLM if Atari had decided to do so ;) . Really would have hardly added any extra cost, but just like by adding MIDI ports to the ST, this could have breathed new life into the 8-bits. BITD, it cost nearly $250 to add a MIDIMATE to your XL computer, that probably only cost you $199 to buy from Toys'R'Us.

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I was asked to provide a bit more info on how I cut out the piece of the motherboard where the SIO2MIDI was inserted, as well as details on making the holes for the MIDI jacks. Unfortunately this comes after the fact, since I didn't document every step while I was doing it. So an 800XL case will be substituted for this mock picture session.

 

So first lets talk about how I cut out the chunk of the original motherboard...

 

post-42561-0-00412100-1553797288.jpg

 

In this enlarged image you can see the saw cut edges which resulted from using a hacksaw. Yep that's how it was done, a steady hand and a hacksaw. But before I did that, I positioned the modified SIO2MIDI board where there was the least amount of stuff in the way, marked the edges on the motherboard, and proceeded with a cut ever so slightly less than the overall width of the SIO2MIDI board. I had also previously marked the depth of the cut out using the SIO2MIDI board as a template, this is the depth of the cut to be made with the hacksaw. After cutting both sides down to the depth mark, I then took a straight edge and a razor knife to score a line between the two saw cuts using the depth line I previously marked. After scoring it several times (the more the better), I used a crescent wrench set to the thickness of the motherboard to allow me to bend and break off the piece. This was followed up with a flat file, all the while checking for fit with my SIO2MIDI board.

 

After making sure that the two pieces fit together, I stuffed and soldered the SIO2MIDI board with all of it's required components, with the exception of using a 2-pin header in place of the LED (this will require filing off the corners of the header pins to fit the board). Then mix up and use some quick set epoxy in a few spots to hold the board in place. After all of the trace jumpers have been installed, you'll follow up with a bunch of epoxy to secure the two boards together (see the pictures in my first post for what this looks like).

 

Now for the DIN jack holes...

 

I start by first laying down some painters tape even and level with the bottom of the hole on the existing power jack. This will act like a guide later on.

 

post-42561-0-20922600-1553797295_thumb.jpg

 

Next you'll need to measure the centers of the new jacks from the power jack and begin transferring that information to the case.

 

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I then use a circle template that is slightly smaller than the holes I wish to make to give me a better idea of the hole's area.

 

post-42561-0-22607300-1553797320_thumb.jpg

 

Here are the Tools of the Trade that will be required.

 

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Now for the fun and scary part ;) . Because some of the holes are being made over existing holes, some not round, a file is the best place to start. Try to match the drawn circles as best you can. After doing this, use the Uni-Bit to enlarge those circles to the final diameter (11/16"). A different approach will be used on the center hole which is being made in virgin territory where no previous holes exist. Start with a 3/16" drill bit to create the starting hole in the center, then follow this up with the Uni-Bit.

 

After the holes are completed, debur them inside and out (I had a big countersink tool, but using the Uni-Bit tool by hand should also work). A final touch would be to take a rag with a small amount of Acetone on it, and wipe the inside of the hole to smooth it out. Be careful on this last part that you do not get any on the outer face of the case, or any drips on anything else made from plastic.

 

Sorry I wasn't able to get even more detailed with the pics, but I wasn't about to actually put holes in that 800XL case.

 

 

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Just to add a trick for cleaning up any case mods like that. A tiny bit of acetone on a q-tip will smooth and "seal" the area as acetone melts the plastic. Tiny amount - it should only take a second for the small amount to evaporate and leave the mod smooth.

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I have respect for anyone who can use a hacksaw on a PCB and have the modified board work better than before they began.

 

I usually don't take a hacksaw to a board until after it's already broken - only to salvage connectors or components.

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Hahaha! I do stuff and I mean to document it but I get so into it.. I forget!!!!

 

Looks great!

 

Yeah that happened to me for sure on this project, which became a 2 day marathon modding session. I was so into it, that I forgot to eat until the end of each day, and when I was done I had one hell of a mess to clean up. The funny part was during the clean-up I was finding tools scattered everywhere, and was quite flabbergasted that I had used all of them :grin: .

 

 

I have respect for anyone who can use a hacksaw on a PCB and have the modified board work better than before they began.

 

Comes from years of tearing stuff apart and trying to rebuild it in a new form :) .

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@Michael:

 

I see that you used an original 2364 Rev.C BASIC ROM, just thought I'd point out that the 600XL PCB Revision you used is able to be rejumpered to accept a 2764 EPROM. The socket has to be changed/extended using the existing 28-pin footprint as well.

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@Michael:

 

I see that you used an original 2364 Rev.C BASIC ROM, just thought I'd point out that the 600XL PCB Revision you used is able to be rejumpered to accept a 2764 EPROM. The socket has to be changed/extended using the existing 28-pin footprint as well.

 

Thanks for the tip. That would allow me to burn Altirra Basic and use that instead :) .

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I just discovered that @flashjazzcat did an internal installation of a SIO2MIDI board in a 130XE of a similar nature to what I did on this 600XL about 5 months prior to his. Essentially we both performed a board surgery where a SIO2MIDI size chunk of the motherboard PCB was removed (where the removed RF module originally resided), and then the MIDI board was inserted and glued into place. Of course his job was probably much better looking then the one I did, where I got a bit excessive with the glue. Interesting how great minds think a like :)

 

 

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Wow. So SpartaDOS will see the CF drive just as if it was a SIDE2? What about putting the CD activity LED behind the transparent window above the RESET text?

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28 minutes ago, Sugarland said:

Wow. So SpartaDOS will see the CF drive just as if it was a SIDE2?

Yep, except now you still have a free cartridge port for anything you may wish to plug into it ;)

 

Oh and the Loader sees it the same as a SIDE2, so any FAT files (XEX, ATR) you have copied to it will be available to launch.

 

Quote

What about putting the CD activity LED behind the transparent window above the RESET text?

Yeah that would have probably been a better idea, but I had already put it where it was back in 2019 for a MIDI active indication (hole drilled - no going back). It does make more sense to repurpose it for CF activity instead.

 

hdd-led_orig.jpg.f039aaddffa9b73e94e8e7dfd5553360.jpg

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I finally found a purpose for one of the auxiliary control outputs on the TK-II-PBJ that I installed. A1 gets connected to the swap button input on the XL-CF4 board. Now all I have to do is press ALT+1 to swap disks - no holes need to be drilled in the case for a push button switch 🥳

 

tk-ii-pbj_top_assy_complete.jpg

 

https://ataribits.weebly.com/tk-ii.html

 

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