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I was leaning that way... I knew about the RAMDAC, had missed the total VRAM. I guess I need to see if the "red" card will come to life. I sense some tinker-time coming this weekend. 😊

I'm back on this thread since my question is not limited to the 24X... Looking above, you can see the pics of my "red" card has a 24X 2.0 ROM (which I have posted in the other 24X-specific thread). However... when looking at my other 24X card, I spotted a significant design difference. Here...

Pretty sure I have a PrecClr 24X with a 1.4(?) ROM - I'll pull it out of my IIcx and have a look. Might have others down in my storage unit. Stay tuned.

No problem my end. Will be good to have a repo. Do check my 24X dump first. The 24XP has been confirmed working.

Awesome! Great that it worked for you! 👍

PrecisionColor 24XP ROM 2.0 - this is from a working card. :)

And this (warning, it's a scan, so large file!) - https://vintageapple.org/macmanuals/pdf/Macintosh_II_manual_alt_1986.pdf Page 207 : So... 8Mb = 2 x banks of 4 x 1Mb should be fine.

And then we have this -- https://www.applerepairmanuals.com/the_manuals_are_in_here/Macintosh_II_IIx_IIfx.pdf Which implies 8Mb (though that would require 1Mb SIMMs in both banks) is the Maximum. :unsure:

https://support.apple.com/kb/sp193?locale=en_US Implies that 4Mb can be used - but only in Bank B. I'm sure I've run my original Mac II with 8Mb = 1Mb SIMMs in Banks A and B.

OK, so... here's the 2.0 dump. CAUTION : I have a feeling this card was not working properly (which is why I have it loose). So be warned if you try this dump and it doesn't work. I will try the card again this coming w/e and report back. In addition, looking at the HEX, I was expecting to...

Um... three, perhaps. 😀

a few... ...and pretty sure I have more in my storage unit. 🙄 Once you've adjusted, we can sort through the other things we've been discussing. 😀

So we're in a race - who gets something first!! 😉 FYI, my laptop that I use to drive my TL866II was flat, charging now, so hope to have some dumps soon.....

Question - in the pic with the red pcb, don't you need to use the top-most pins on RN6? Those are the only ones that are not connected. :unsure:

Interesting. Found a guy on eBay selling a pair of UV erasable '512s for a little over a fiver, so ordered some. What about EEPROMs? Aren't there pin-compatible ones of those that might work?

Don't want to hijack, but I have a small pile of original style battery 'clips' if those are of any interest. Welcome back btw. :)

Spot on! I noticed in the pic that the label was lifting a little on the 24X, so, I gently gave it some assistance... So... 27xxx - does that mean these are EPROM, and therefore, one-shot, NOT erasable? :unsure:

https://68kmla.org/bb/index.php?threads/whats-the-difference-between-the-various-radius-24-cards.26853/post-486605 I'll try to get the ROM dumped this w/e. @Phipli - I'd rather not pull the labels, do you know what "type" EEPROM these use? Looks like PLCC32 footprint.

Oooo... look what else I found : More importantly :

Ahhhh... 😀