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Prototyping Boards


Ksarul

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As I reached near completion on component soldering for the first TI 128K card, an interesting thing I saw on Mainbyte's site piqued my interest. There's a picture there of a full-size PEB Extender board--something really easy to build, and very useful when building and testing boards. I spent about an hour and did a complete layout for one (I already have lots of the necessary connectors)--but is there enough interest in one of these that I can justify doing a run of 10 or so of them?

 

Now I just have to wait for the last random components for the 128K card to arrive. . .

 

I also started soldering on one of the Protoboards (to test the components in the buffer interfaces and such).

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As I reached near completion on component soldering for the first TI 128K card, an interesting thing I saw on Mainbyte's site piqued my interest. There's a picture there of a full-size PEB Extender board--something really easy to build, and very useful when building and testing boards. I spent about an hour and did a complete layout for one (I already have lots of the necessary connectors)--but is there enough interest in one of these that I can justify doing a run of 10 or so of them?

 

Now I just have to wait for the last random components for the 128K card to arrive. . .

 

I also started soldering on one of the Protoboards (to test the components in the buffer interfaces and such).

 

mememe

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I figured you'd chime in on this one--and maybe Marc, Ciro, Jens-Eike, Tim (if he doesn't already have one), and one or two others. If I get six folks looking for one I'll do the run on these, as that will commit enough of them that I can mostly break even.

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I have about 100 bus connectors with really long wire wrap pins on them. Bend them in a bit and you have the perfect extension board connector. Here's the one on Mainbyte that uses pretty much the same system:

 

http://www.mainbyte.com/ti99/hardware/peb/other_cards/more_items.html

 

Just look at the second board down to see how easy it is to solve the connector problem. When I saw the connector used there, I realized I could make these quickly, as I have about 100 of them to work with. . .you have ro take the boards out of their cases to work with them (exactly what you'd expect to do if you were troubleshooting), or carefully saw the two side tabs off.

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I figured you'd chime in on this one--and maybe Marc, Ciro, Jens-Eike, Tim (if he doesn't already have one), and one or two others. If I get six folks looking for one I'll do the run on these, as that will commit enough of them that I can mostly break even.

 

I do have one that I use when I repair Myarc and other cards. Makes it easy to get voltage and other readings. I find my extender can be flakey at times though it isn't clear if the extender or the PEB is the culprit. I might be interested in one.

 

Do you have any need to inspect mine as part of your development?

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Is yours similar to the one on the Mainbyte site? If it is, then I've already got a completed layout for it. Most of the ones I'd seen before that one were just as wide as the connector, so using them could get dicey. This one is a full-sized PEB card (with tabs to put into the cage fingers), but it is also possible to shave the tabs off and put it into a clamshell (all of the necessary holes are present). Then you just cut a hole in the top of the clamshell for the upper connector and you're in business.

 

If you have a copy of ExpressPCB, I can send you the file and you can look at it to see if it would work as well or better than the one you have. Pictures are good too. I can usually work very well from a high-res set of front/back photos.

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I have about 100 bus connectors with really long wire wrap pins on them. Bend them in a bit and you have the perfect extension board connector. Here's the one on Mainbyte that uses pretty much the same system:

 

http://www.mainbyte.com/ti99/hardware/peb/other_cards/more_items.html

 

 

I followed the link after I read your earlier post. The extender on Ron's site is different than mine. ;) I am under the impression there are very few of these floating around, if any. I've attached two pictures of my extender.

post-25764-0-20745400-1400388554_thumb.jpg

post-25764-0-19120000-1400388561_thumb.jpg

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I had to look at that one carefully to see exactly how the connections danced between the sides of the board, but I like it. I may add something similar to mine now, as I like the idea of being able to measure each signal on one side. That card is also about two and a half inches taller than a standard PEB board, isn't it? The holes are at the standard points for the clamshell, correct?

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I took Tim's board and ran with it, so sometime later today I should have something closer to his board than the one that was on Mainbyte. His has the advantage of a complete set of test points below the connector, which should help a lot when troubleshooting. I numbered everything too--both in the metal and on the component layer.

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I had to look at that one carefully to see exactly how the connections danced between the sides of the board, but I like it. I may add something similar to mine now, as I like the idea of being able to measure each signal on one side. That card is also about two and a half inches taller than a standard PEB board, isn't it? The holes are at the standard points for the clamshell, correct?

I will take some measurements this week. I suspect you are right about the clamshell holes, though I have never had cause to check :) The card itself is VERY sturdy given its width ensures it is steadied by both the front and back slots. In fact, it might be worth extending the height slightly to allow better access to the signal holes. I thought about taping over the power holes to avoid shorting the signal bus, though I have yet to do so. Maybe a mask over those traces would work?

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I actually have most of the board masked, Tim. The area around the power holes isn't covered now, but I can easily do that. I just left an area about 2/3 of an inch wide unmasked at the holes, so that you could hit the hole or the trace immediately above/below it and still get a reading.

 

I do have more than enough to make an order, so these will be next on my order list. I'll have to do another order of 512K cartridges after that, as those are selling pretty steadily and I'll run out by the middle of June at this rate. . .

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<snip> I'll have to do another order of 512K cartridges after that, as those are selling pretty steadily and I'll run out by the middle of June at this rate. . .

 

I like that, and hope my programming efforts contributed to it. :) And I want to purchase 2 of them, let me know when you have 2 available.

 

Thanks,

 

Gazoo

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I'll have several available after my assembly work on Friday, so you can get them pretty much any time. I already have your address, so preparing them for shipping isn't a problem either. :-D I still have to ship you that Atmega I got for you when I ordered a few of them for testing. . .

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I just saw a somewhat interesting extender board intended for S-100 systems that may have utility for us as well--it adds some circuitry to the board so that you can look at signals--high, low, and transitioning. Each type is displayed with an LED. Here's the link:

 

http://s100computers.com/My%20System%20Pages/Extender%20Board/Extender%20Board.htm

 

I might even be able to fit this circuit on the bottom right area of the board, since it needs a 5V regulator (it will be a bit tight though). Thoughts?

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