68kMLA Classic Interface

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Classic/MicroMac Performer - Hack Possible? - Clearance Issues?

Posted by: Trash80toHP_Mini on 2025-06-01 08:27:56

Haven't got a Macintosh Classic, but the unavailable socket for its 68000 has been bothering me no end since I kicked off the Performer clone project @Bolle pulled off when I shipped my Performer to him.

May be a bit ugly, but I think we might be able to pull off this bodge?

1 - methinks the Classic's CPU is SMT, not thruhole? That would be a lot uglier than pictured, but still possible?
2 - will the Classic run off a DIP64 68000 socketed to the Performer?
3 - is there enough clearance above the Logic Board for such a contraption?

If the Classic CPU is socketed as I suspect, an intersticial adapter will be required.

Posted by: Trash80toHP_Mini on 2025-06-01 08:41:48

Answered one of my questions, silly of me to wonder about it:

So development of a DIP adapter board will be required. Breaking the PLCC pads out with a castellated(?) SMT PCB looks the ticket?

1 - might running the 68000 lines to interface with the SE PDS suffice or will be offsetting to SMT headers be required?
2 - do components next to the CPU preclude an offset?
3 - looks like the opening might be the limiting factor?

Guessing a Classic specific rework of the Performer might be the way to go for this?

Posted by: Trash80toHP_Mini on 2025-06-01 09:34:47

KISS update: looks like ringing the Classic's 68000 pads with RA .5 inch pitch headers or sockets for them simplifies a rework of the baseline Performer design. Just rework the standard thruhole/unobtanium socket interface to support the "ringed" .5 inch header/socket interface within its footprint?

Requirement of desoldering the Classic's CPU/installing .5 inch pitch connector bodge is still a serious project, but might be worthwhile?

Dunno, whatcha think?

Posted by: Trash80toHP_Mini on 2025-06-01 10:04:08

KISS update 2: taking a cue from the ugly Compact Mac interface sans Killy Klip here.

Looks possible to leave the Classic's PLCC CPU in place. Soldering .5 inch pitch headers all around simplifies things considerably.

Baseline Performer design would be revamped slightly. Only a .5 inch SIP connector adaptation within the existing socket footprint would be required. Spreading the thruholes out just a tad to perfectly match up with headers ringing the CPU looks like the way to go?

The offset mess of the non-Killy Klip 128k/512k/Plus interface is avoided entirely and hack would be reversible by desoldering headers and cleaning up using solder braid. The CPU legs might be tinned and shiny afterward? But appearance isn't everything. 😉

Posted by: Trash80toHP_Mini on 2025-06-02 20:41:00

Thruhole PLCC68 sockets seem to be available. Is this what folks have been saying is unobtanium?

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There seem to be a few listings for thruhole sockets and plenty for SMT Socket listings. The sockets on Performer boards for the Classic look deeper, is that the problem and neither available socket type is usable?

Dunno, confused. Found these looking for the SMT pad footprint.