Reverse Engineering the Macintosh SE PCB & Custom Chips for 1:1 reproduction

[Kai Robinson]

Well, they're here.... GND tests show... THE EXCLUSION WORKS!!!  The rear I/O should now be good to go, it's not shorted anymore, and the rear ADB and serial ports are grounded correctly now. 

 

[techknight]

Good. lets hope for a successfull boot

 

[Kai Robinson]

I also went all in and got 10 boards - so there's a few more that'll be free to go out - and there's still one piece of 'wall art' available

 

[landoGriffin]

Those are truly a thing of beauty! 

 

[Kai Robinson]

OK - i found a supplier of DB19F connectors for PCB's - exxos store! The Atari community use them, too - i bought a few from there for the SE's

 

[techknight]

OK - i found a supplier of DB19F connectors for PCB's - exxos store! The Atari community use them, too - i bought a few from there for the SE's

yea, I think it was a group effort with Steve Chamberlin, and a few others to get those DB19's newly manufactured. 

I think it was the male side, but I cant remember exactly. 

 

[archer174]

yea, I think it was a group effort with Steve Chamberlin, and a few others to get those DB19's newly manufactured. 

I think it was the male side, but I cant remember exactly. 

Yes, male solder cup connectors only. I was quoted a minimum of $25K to do the female board mount version... 

 

[karrots]

In regards to the RTC replacement. If you have to build an adapter board anyway could you not just put an RTC chip + translator AVR on the board. Use the RTC to keep time then the AVR for PRAM + comms translation. If a pulse is needed pick one with that output and map it to the pinout.

Totally speaking off the cuff.

 

[quorten]

RTC chip + translator AVR is indeed totally another possibility that would allow for using ATTiny85 in one of the smaller package sizes.  I'm guessing the main benefit of this layout would be potentially reduced power consumption... due to the increased complexity of having two chips rather than one, I'd guess that's something only to investigate if we're having trouble with the ATTiny87 consuming too much power in sleep mode with the asynchronous timer.

In any case, (1) if you simply want to get a bootable Macintosh with a reasonably well functioning RTC, the ATTiny85 approach should ready to go, (2) getting accurate time entails ATTiny87 and adapter board, and (3) there may be a final upgrade if we want to reduce power consumption.

 

[maceffects]

Yes, male solder cup connectors only. I was quoted a minimum of $25K to do the female board mount version... 

Wow!  I had no idea those were that expensive.  I'd almost thing it would be easier to engineer new tooling and do it yourself or hire someone to assemble.  After looking at it, I'm sure its <$5000 in tooling.  Such a crazy thing to be rare.  I truly had no idea. 

 

[Torbar]

Did you send off one of your boards to RetroManCave?

https://www.youtube.com/watch?v=Z4HD1jvzuS8

 

[motosega]

I've seen solder cup db connectors soldered to a double sided pcb edge, maybe it's possible to make an adapter pcb?

 

[Kai Robinson]

@Torbar Neil's a friend of mine - was up there a few weeks ago for my holiday, got drunk in his lounge - i took one of my dead ones to him for a wall art thing in the cave

 

 

[Phipli]

Did you send off one of your boards to RetroManCave?

https://www.youtube.com/watch?v=Z4HD1jvzuS8

Torbar - I did spot the silk screen says "Hello cave dwellers"

 

[Torbar]

@Kai Robinson cool!  He has a great channel, and seems like a cool guy!  I have one of his calendars that he was selling for charity last year hanging on my wall

@Phipli just noticed that! nice little easter egg

 

[Daniël]

Did you send off one of your boards to RetroManCave?

https://www.youtube.com/watch?v=Z4HD1jvzuS8

I know @Kai Robinson has appeared on the channel, I believe it was the Silicon Graphics Octane video(s).

 

[Kai Robinson]

Yep. SGI Octane Part 2 - was my Octane i donated

 

[Kai Robinson]

@quorten I think the ATTiny 85 would suffice for most people - is the time drift realllly that significant? Btw i found this, might be useful: 

 

[Trash80toHP_Mini]

For the FDD connector, why not alternate thruhole rows for a 20 pin Female Edge card connector with the standard 19pin D-Sub? That way DB or Edge Card connectors could be installed. Development of any future FDD doohickies could use edge card connections for tighter fit to the case sans connector part count.

FloppyEMU adapter like BMOW's would be soldertail DB sandwiched to 20 pin edge card PCB to rather than DIP header.

https://www.sullinscorp.com/drawings/54____C___DRA_,_C10876-E.pdf

Connector in PDF has threaded lug mount option

 

[Kai Robinson]

Hmm. Possible - although i'd rather just use the proper connector at least for now: https://www.exxoshost.co.uk/atari/store2/ - Item 0084.