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1450 XLD motherboard build, assorted questions


Vandal968

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I'm just about finished modeling the adapter panel to convert a 1200XL case into a 1400XL case. I just need to finalize the design of the transition pieces and do the lettering.

 

cheers,

c

You, sir, are amazing as are your awesome tools. I would love to have a mill at my disposal.

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You, sir, are amazing as are your awesome tools. I would love to have a mill at my disposal.

 

Bobotech,

thank you. I don't think think I'm going to use the cnc mill on this one though, a block of ABS big enough to cut this part from is around $40 and I'll be able to get Shapeways to rapid prototype it for around the same cost and much less effort. The SIO2SD enclosure should be here by Friday, and how it turns out will help me make my final decision.

 

Your expertise would have saved me many tearful hours in the kitchen with a dremel over the years! :)

 

flashjazzcat,

just as NASA sent duct tape to the moon, there will always be a need for dremel skills ;)

 

cheers,

c

Edited by Vandal968
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You, sir, are amazing as are your awesome tools. I would love to have a mill at my disposal.

 

Bobotech,

thank you. I don't think think I'm going to use the cnc mill on this one though, a block of ABS big enough to cut this part from is around $40 and I'll be able to get Shapeways to rapid prototype it for around the same cost and much less effort. The SIO2SD enclosure should be here by Friday, and how it turns out will help me make my final decision.

 

Your expertise would have saved me many tearful hours in the kitchen with a dremel over the years! :)

 

flashjazzcat,

just as NASA sent duct tape to the moon, there will always be a need for dremel skills ;)

 

cheers,

c

 

You need to get one of those awesome plastic prototyping printers. The ones that print plastic and can create objects. I don't know what they are called but I can see you making lots of magic with them.

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You need to get one of those awesome plastic prototyping printers. The ones that print plastic and can create objects. I don't know what they are called but I can see you making lots of magic with them.

I built a 3D printer last year, it's a Makerbot cupcake clone that I call Fakerbot. There are a lot of shortcomings to the Makerbot design, so I addressed two of the biggest ones by designing a new Z-stage and extruder. Even so, the quality is not adequate for these Atari parts. Video here:

 

cheers,

c

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I will update again very soon to reflect some additional information that is in this thread but wasn't in the BOM when I posted (like the modem xformer P/N that worked well and why to never use W4) but there are no errors in the BOM already posted and only three or four items will have additional information added about them.

 

cheers,

c

 

Corey, I went through the messages in this thread and saw one difference in the BOM:

Is C134 a .1uf 10v Electrolytic or 1uf 10v Electrolytic?

Did you find a source for the relay? looks similar to what I have seen in some ham radios...

 

Jay

 

P.S. have you had a chance to update the BOM?

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I fired up the 1450 yesterday to play some games. My usual machine is an 800XL since I've got a couple of them and if my kid breaks one it won't be the end of the world. Turned it on, and the screen came up in black and white. Hmmmm... it was color the last time I used it. Then I remembered that I did the 800XL video fix last week and have the cable hooked up to s-video instead of composite. Is it possible that Atari did the same stupid missing-chroma thing on their flagship machine?! I started poking around, and you bet they did! Chroma is missing, the impedence matching is wrong, etc. All of the typical 800XL errors EXCEPT that the 1450 has very vibrant colors. I started investigating further to see if the 1450 uses the 800XL or 1200XL video circuitry. I actually expected 1200XL because of the very vibrant colors, but no, it's set-up almost exactly the same as the 800XL. There is only one missing component that I've discovered so far. I added the missing chroma line, and got some nice color. Then I removed the infamous filter cap (bringing it in and out of the circuit while powered-on to test the effect first). It makes a slight improvement to clarity but reduces the color saturation a little (it did not have this effect on my 800XL). The impedence fix made no visible difference, so I'm still looking into that one. So, 1450's with super-video, coming soon. If ordering parts, get two 75 ohm resistors while you're at it. You're also going to need a 100 ohm, but your donor machine should have plenty of those.

 

This would have been easier to figure out if I had a spare 1450 board to look at. I'd still love to get my hands on another one if anyone's got a spare (hint, hint ;)

 

cheers,

c

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Hmmm, interesting... That was one thing I was going to do was compare video circuitry between the xl's and xe's before I added that section on the mobo.

I went through the schematics making up a list of parts and compared my list against yours and looks like i"m ready to start soldering components today :)

Still need to get a 40watt iron to remove the TV Modulator from a 800XL...

 

Looks like those folks who bought multiple 1450 mobo's (>2), are treating those like 40k diamonds and don't want to let one go. I too am still looking for a 2nd to build up, but no one else besides mimo has contacted me... Hopefully we'll find another gracious soul to build our 2nd 1400/1450 :)

 

Jay

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Hmmm, interesting... That was one thing I was going to do was compare video circuitry between the xl's and xe's before I added that section on the mobo.

I went through the schematics making up a list of parts and compared my list against yours and looks like i"m ready to start soldering components today :)

Still need to get a 40watt iron to remove the TV Modulator from a 800XL...

 

Looks like those folks who bought multiple 1450 mobo's (>2), are treating those like 40k diamonds and don't want to let one go. I too am still looking for a 2nd to build up, but no one else besides mimo has contacted me... Hopefully we'll find another gracious soul to build our 2nd 1400/1450 :)

 

Jay

You guys with one are lucky compared to us with zero :_(

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Just get yourself a 1200XL and do some mods. I love that they built a 1450/1400, but I don't feel the need to have one at all with my heavily modded 1200XL sitting on my desk. Even with the cost of all the mods, I'm way ahead of the game on cash spent.

 

Of course, if you really want the speech, you're out of luck, but I happen to own a fully functional Heathkit Hero-1 robot, which has the same sound chip.

 

I'm totally fine with vicariously enjoying this build...

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Just get yourself a 1200XL and do some mods. I love that they built a 1450/1400, but I don't feel the need to have one at all with my heavily modded 1200XL sitting on my desk. Even with the cost of all the mods, I'm way ahead of the game on cash spent.

 

...

 

I'm totally fine with vicariously enjoying this build...

Ditto.

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I heard back from Curt last night. He has located the films for the daughtercard and will send them to me hopefully by the weekend. Once I've got them, I'll convert to vector so I can etch the photo-resist on the laser and I'll make an nc file for the drill pattern. Can't wait to finish this up and start on the case. All remaining electronic components should be here by tomorrow.

 

cheers,

v

 

Could you post the films of the daughter board? I'll be etching and drilling mine :)

 

Thanks,

Jay

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Could you post the films of the daughter board? I'll be etching and drilling mine :)

 

Thanks,

Jay

Curt never sent me those films, so, while waiting, I decided to try the motherboard without the daughtercard and using the other modem chip. There was a high pucker-factor since no one seems to have a board with the other chip, so I couldn't verify whether it necessitated any other changes on the mobo or not. My EE buddy took a look at the board and felt that it was unlikely to fry anything, the most likely outcome was that it just wouldn't work. It DID work however :)

 

Don't worry about the daugtercard, and you won't need the components on the second tab of the BOM. I, of course, have two sets of those....

 

cheers,

c

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Could someone point me to the schematic of the daughtercard that uses the TMS99532 chip?

 

I know I've seen it before, but just can't seem to find the bugger.

 

Thanks...

 

Still haven't found the hand drawn schematic that I think I saw a few months back, but have found the pictures of a beadboard assembled version. I've drawn a rough diagram of the component layout and wiring, now on to phase two and draw a nice schematic from that...

Edited by AtariGeezer
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Why not just buy the $4 chip and do it without the daughtercard like I did. It would save you some hassle and about $15 worth of connectors. You won't be able to have a 100% authentic-looking board anyway since the modem connectors are no longer available in red and the floppy data connector & telco xformer aren't available in the exact style. If you really want the daughtercard for some reason, there were some nice photos posted in this thread (top & bottom) a while ago. If you are going that route, it would be nice to recreate the original board with all markings, etc and have a batch of them made. That was my original plan, to make a batch, keep two and offer the spares to anyone else building a 1450 board.

 

cheers,

c

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Why not just buy the $4 chip and do it without the daughtercard like I did. It would save you some hassle and about $15 worth of connectors. You won't be able to have a 100% authentic-looking board anyway since the modem connectors are no longer available in red and the floppy data connector & telco xformer aren't available in the exact style. If you really want the daughtercard for some reason, there were some nice photos posted in this thread (top & bottom) a while ago. If you are going that route, it would be nice to recreate the original board with all markings, etc and have a batch of them made. That was my original plan, to make a batch, keep two and offer the spares to anyone else building a 1450 board.

 

cheers,

c

 

Actually, I plan on doing both modem types since I have all of the parts required except the connectors. I saw some of the red ones at the parts store, so I'll see if they have a complete set.

I saw pics of the top of the daughtercard, but not the bottom. I'll recheck...

 

Nope, no bottom pics in this thread...

 

Jay

Edited by AtariGeezer
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