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Reverse Engineering the Macintosh Classic PCB for 1:1 reproduction

davidg5678

Well-known member
@Trash80toHP_Mini's milling idea sounds promising and do-able to me. I wish I understood the resin mold part though.
I think the idea of resin is to stop the irregularly-shaped logic board from wobbling around, or from being anything but perfectly level as the milling machine slowly removes each layer. Honestly, with every component removed from the board (thus making it flat), this may not be necessary. As far as I know, somehow, milling machines should be able to clamp to a thin rectangle pretty well. They should also be precise enough to remove thousandths of an inch from the PCB, too. 

 

Trash80toHP_Mini

NIGHT STALKER
I think the idea of resin is to stop the irregularly-shaped logic board from wobbling around, or from being anything but perfectly level as the milling machine slowly removes each layer.


That's my take on it as well, I hope someone familiar with this process chimes in at some point. Meanwhile, WAGs about the process would be:

- remove components without worrying all that much about irregular solder surface cleanup.

- moosh the board down into the epoxy with a press to keep its surface roughly parallel to the base of the press with the top surface visible.

- clamp rough casting and mill the top surface to rough flatness just shy of the PCB and mill sides of the casting to a precise rectangle

- clamp the bottom surface to a drill press like device (forgot the name)

- take enough measurements to bare copper (maybe solder mask?) to determine the plane of the PCB in relation to casting base

- clamp upside down and mill the base to match to match top plane and remaining rough sides of the casting

At some point you'd probably want to measure and mill the casting to square it up to edges of the PCB for precision clamping and registration on the scanner.

 

Scott Squires

Well-known member
I understood the purpose of the resin, but not being a mechanical engineer person didn't understand how one would accomplish it. Thanks @Trash80toHP_Mini for explaining one possible way to do it. Sounds like it might be more suited to a CNC mill (for the leveling part) than a manual mill like I had in my head.

1 oz copper is 0.035 mm thick... that's some mighty precise leveling to pull off.

 

Trash80toHP_Mini

NIGHT STALKER
I understood the purpose of the resin, but not being a mechanical engineer person didn't understand how one would accomplish it. Thanks @Trash80toHP_Mini for explaining one possible way to do it. Sounds like it might be more suited to a CNC mill (for the leveling part) than a manual mill like I had in my head.

1 oz copper is 0.035 mm thick... that's some mighty precise leveling to pull off.


Mom's dad was a master machinist at GE during WWII and well into my youth. I'll bet he could have pulled this off using the manual tools in his basement machine shops. He made and fixed the machines used to fabricate the machines that produced the factory floor machines used roll out mass quantities of war machines.

.035mm = 1.38 mil, how much of that thick copper cladding did you want shaved off? [:)]

 
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Kai Robinson

Well-known member
With so many months worth of content just gone - i'm not going to waste my time trying to fill in the blanks.

Archive.org has a backup of this thread upto May, i suggest anyone seeing this and wanting to find out what happened next, can view it there, or see the abridged version at the Phoenix Engineering Wiki.

Anyone that ordered a board from me and is still waiting, or has issues, please send me an email at kai(underscore)robinson[at]hotmail|dot|com - i won't be relying on forum messages again.
 

cheesestraws

Well-known member
That you are making an utter tit of yourself.

For someone who said how much they liked how little the Mac community is like the Amiga community, you're behaving like a stereotypical Amiga user, thinking that your temper tantrum should have seismic importance for everyone else and actively trying to make other people miserable.

Stay or go, but do either, don't keep popping back and yelling "ONE MORE THING". I don't care: I am deeply sad and depressed that you are not the person I thought you might be.
 

cheesestraws

Well-known member
I wish to withdraw my previous post. I will not pretend I did not type it, but I acknowledge that I should not have. Sorry, Kai.
 

AndyO

Well-known member
@Kai Robinson - Having experienced similar loss of extensive and invaluable work myself elsewhere, I totally understand the frustration, and the wish to find a more stable platform to share your efforts.

But for one tiny reason, I hope you reconsider. It's this: The more the ongoing efforts to support vintage systems and their owners fragments into ever-more discrete places, the harder it is for us to find out what is even possible, let alone available.

I joined here earlier this year precisely because it contained your work (and that of others) which promised the possibility of putting old Macs I own back into practical and valuable use. Without finding this very thread in March this year, I wouldn't have even known there was a project to re-engineer a board for my Classic, so I wouldn't have known to go looking anywhere else to find one.

Refusing to continue updating your work here is your right, and would be understandable, but after a time it would drop out of visibility, and once again, the knowledge that someone, somewhere, is doing this great work would be lost again to people like me who won't know to look for you.

In your shoes, I'd be mad as hell, but even so, I 'd be inclined to think that taking my talent elsewhere would maybe be punishing the wrong people.

But, thanks anyway, for demonstrating that the impossible isn't!
 

Kai Robinson

Well-known member
@Kai Robinson - Having experienced similar loss of extensive and invaluable work myself elsewhere, I totally understand the frustration, and the wish to find a more stable platform to share your efforts.

But for one tiny reason, I hope you reconsider. It's this: The more the ongoing efforts to support vintage systems and their owners fragments into ever-more discrete places, the harder it is for us to find out what is even possible, let alone available.

I joined here earlier this year precisely because it contained your work (and that of others) which promised the possibility of putting old Macs I own back into practical and valuable use. Without finding this very thread in March this year, I wouldn't have even known there was a project to re-engineer a board for my Classic, so I wouldn't have known to go looking anywhere else to find one.

Refusing to continue updating your work here is your right, and would be understandable, but after a time it would drop out of visibility, and once again, the knowledge that someone, somewhere, is doing this great work would be lost again to people like me who won't know to look for you.

In your shoes, I'd be mad as hell, but even so, I 'd be inclined to think that taking my talent elsewhere would maybe be punishing the wrong people.

But, thanks anyway, for demonstrating that the impossible isn't!

Hi Andy.

I think I'm gonna just quit developing anything, at least for now. All projects are cancelled.

Any enjoyment that I got from this hobby has sailed out the window now.

Maybe the one good thing to come from this is that people will know that these things are possible.

Thanks for your kind words.
 

markyb86

Well-known member
I think I'm gonna just quit developing anything, at least for now. All projects are cancelled.

Any enjoyment that I got from this hobby has sailed out the window now.
This is like deciding to stop working on cars because you lost the maintenance receipts... Can't say I understand but do whatever you feel is best man.
 

bdurbrow

Well-known member
Well --

I do understand the frustration of having the rug pulled out from under you; so if you feel that's what you want to do, OK...

... but before you quit completely, can you make sure that all your project files (including the source for any custom tools you may have built) are up somewhere like github, so that others may follow in your footsteps, so-to-speak?
 

Kai Robinson

Well-known member
Well --

I do understand the frustration of having the rug pulled out from under you; so if you feel that's what you want to do, OK...

... but before you quit completely, can you make sure that all your project files (including the source for any custom tools you may have built) are up somewhere like github, so that others may follow in your footsteps, so-to-speak?
I wasn't aware that others were entitled to my work. If I release any of it, it'll be at a time I choose, and if I choose to finish it. Only once finished will I consider posting it.
 

AndyO

Well-known member
Hi Andy.

I think I'm gonna just quit developing anything, at least for now. All projects are cancelled.

Any enjoyment that I got from this hobby has sailed out the window now.

Maybe the one good thing to come from this is that people will know that these things are possible.

Thanks for your kind words.

I hope you decide to reconsider, even if not for a while, but even if not, thanks for your work - which regardless of the recent setback was very obviously much appreciated.
 

bdurbrow

Well-known member
Kai - If I thought I was entitled, you'd be receiving a demand letter with a threat of litigation, bad luck, and smelling like an ogre for the next billion years. ;)

It was just a polite request. I just hate to see good work get abandoned, and lost to the abyss of time... that's all.

As I said, I do understand where you're coming from. I've personally had the rug pulled out from under me more than once.
 

timdorez

Member
Just watched Bruce's final video on his reloaded Classic board build. How awesome is that !?
Huge congrats to you @Kai Robinson for the reverse engineering efforts and to Bruce for painstakingly putting that board together and looking for faults too ! 👏

I didn't follow much of the process with this one contrary to the SE but it feels like you got way quicker at it ! So awesome !

Now, one thing is certain : I want my limited edition board. 😁
It's fair to say I pretty much started a collection by now.
 
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