Hello this is a crosspost from another site (68kmla), We know that the TechStep was a short lived but very useful tool and it can test many components and issues on these Old Macs. A team of three people have made all of this possible. Below you will find a .zip file containing all of the resources, build guides, documentation, .stl files for the 3D printable cases, as well as the ROM images and boards themselves. Each category has been broken down into folders for your use, enjoy!
Creators of this project are
@jajan547,
@Elemenoh, and
@SuperSVGA
Before I begin, I just wish to express my sincere amazement and appreciate of this amazing project. The work that went into making this a reality is simply astounding!
I now have some questions and comments about the contents of the attachment in the opening post:
Let's go about this assuming that folks who find this thread and who are interested in building themselves a ROM pack have zero experience making PCBs, programming chips, etc.
QUESTIONS/COMMENTS:
1. What are the differences between TechStep Cartridge Rev1 & Rev2? (The fact both are included implies both may be needed, depending on the use case.)
2. There are two "Cart1" and two "Cart4" files with one of each having "M95020" in the name with no explanation, and without viewing the Gerber files, it's impossible to know which is which. However, from what I can see, the M95020 version uses all SMD components, while the other version uses a DIP version chip for U2. Even so, when I load each file into the PCBWay interface, only the M95020 version looks right, as shown below. The other Gerber has some serious problems. Could that be a problem with PCBWay's Gerber viewer or that Gerber file?
The Gerber file
without M95020 in the name:
3. Inside each of the Gerber ZIP files, there's a text file that says this...
Clicking that link leads to
this web page:
It's a little confusing because it says in step 1...
- Finish the schematic and PCB design at EasyEDA.
One is then left to wonder: "schematic? what schematic? and how do I finished it?"
I do see this "BOM" of sorts in your archive (opening post attachment)...
But it doesn't list specifics like quantity, resistor tolerance (i.e., does the factory cartridge use 5% tolerance?), and which cartridge name applies to which parts.
I am going about this as a newbie. If a newbie has the goal of making Cartridge 4, for example, they would need to do this:
1. Figure out which Gerber to use, then choose a PCB maker (like PCBWay or JLCPBC) and upload it, then have them build it. Even though it is often said JLCPCB is cheaper than PCBWay, fact is that some folks who've been using PCBWay may wish to stick with them. So knowing how to accomplish PCB creation on PCBWay too may be helpful to some.
2. Figure out which parts one needs to order and what quantity (including the connector), and then determine if the PCB supplier (e.g., PCBWay) can build the board with those parts. PCBWay seems to have an Assembly service and they appear to be able to source parts too. Using their web interface, it seems they Assembly fee would come to US$30, which doesn't include the price of the parts.
3. Upload the STL files for the plastic case to a place that can build the case. PCBWay offers a 3D service, and their build using Resin would cost about US$25 for the 2 required pieces (not including shipping):
4. Figure out what is needed to program the "REVISED" BIN file to the ROM chip, and whether that can be done if one orders an "assembled" PCB from a place like PCBWay. (In other words, what programmer is required, and how does one interface that to the ROM chip for programming, and what software is required?)
5. One then needs to print the labels (contained as PDFs in the attachment in the opening post), and affix them to the 3D printed plastic case.
So any thoughts you can share on the above would be helpful to those wishing to create a finished cartridge, using the files attached to the opening post.
Thanks!