Kinda have to agree. The design / style elements clearly share a lot of DNA, but the Color Classic is so elegant and refined, and the Performa 575 looks weirdly... mutated? Like a Color Classic that took a LOT of roids and skipped leg day for years...
You still have an open trace somewhere.
This is hallmark of a floating digital/control line. Almost as if one of the pullup or pulldown resistors has gone open circuit either the resistor itself, or, the trace/via connecting to it.
Thanks, two hours ago I was half asleep and fact-checking on LEM. Mac II series stuff is correct, no? Nothing there addresses the use of 128MB SIMMs anyway AFAIK? Shoulda' remembered that a whole bunch of late Quadras could be bumped over the 136MB mark when those hit the streets.
Quadra 630 shipped with only in single SIMM Slot configurations. I've been trying to get my grubby little paws on an LC or Performa DOS compatible board or 640 with two slots for twenty years. I have an itching desire to desolder some RAM and jumper RAS lines from those pads to a 128MB SIMM in the "64MB Slot." Heck, if I could find the thing, my original Q630 I would have had that wired up by now.
Meme titles aside, I could not be more excited to now own a Performa 575! This happened last week, as a result of an astonishing act of generosity by @JRL (who donated the 'body' of the Performa, which was in good shape but lacking a motherboard), and an excellent transaction with @hyperneogeo (who sold me a recapped Performa 575 motherboard). The fact that either of those things happened at all is pretty remarkable, but the fact that they both happened on the same day and locally (so no shipping was required) is borderline-insane. Our own @maceffects even reached out to me with an offer of a very-reasonably-priced Ethernet card for the Performa and I've already ordered a new SCSI2SD for it from @inertialcomputing, so it should be fully functional within the next week or so. I did perform a quick test (using the SCSI2SD currently attached to the Color Classic II seen above) and the Performa 575 runs like a champ: