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Inspecting each pin with an oscilloscope, here were my notes: 9 high 5V shorted to 8 8 high 5V shorted to 9 7 ground -> ground on DB15 6 spikey 0.6V 28.5 us blue? -> 9 DB15 5 probably green? + hsync -> 5 DB15 4 hsync 5V 150 ohms to ground shorted to 2 ->15 DB15 3 ?? 5V 2 composite sync 150...

My slot connector board is different than yours. It is part number X10-S10E, as opposed to X10-S10F. The DB9 connector is indeed an odd choice. As someone pointed out, it is not an early VGA connector. It's just what a lot of proprietary monitor/card combos seemed to choose. My test setup...

Holy necrothread! Here is your answer 14 years later, @ojfd This is a Mac LC Mono Display card. Although engineered by "Memory Plus", their work was rebranded and distributed under a number of other names. As you can see, TattleTech is able to see this card and SlotRom can dump the ROM (see...

Cool save!

It might be worth a read of the DV15 technical note (attached) to explain why they needed a special terminator. >> ....a new SCSI chip that provides SCSI data transfer rates up to 3 megabytes per second... >> The reason for the new terminator is that on the Macintosh IIfx and future hardware...

That surprises me. Did you mimic the IIfx terminator by adding a 470 ohm pullup to req (so the total pullup is 150 ohm) along with a 2.2 uF tantalum and 0.01 uF ceramic capacitor to term power? I don't think those are magical values -- but I do think they put some thought into it. The fact...

15.16ms vertical frame rate (65.96 Hz) Voltage of 1.37V is not TTL but not VGA either Horizontal line 18.6 us. From the article below, a 1365x1024 mode is claimed. Maybe with a special cable or driver software? The oldest SuperMac SuperVideo software that I have did not recognize the card...

1024x768 @ 66 Hz. I used a ViewSonic DB15->VGA adapter set to 1024x768 in case it needed monitor sense (I don't think it does) Dell 1708FPt monitor (none of my other monitors would display an image) Image looks this bad. (not caused by photography). Likely due to the voltage and timings being...

I was finally able to get an image from the SuperMac Graphix card. Apple Macintosh II Video Card on primary monitor SuperMac Graphix card on secondary monitor Had to use a Macintosh II, as the monitor jack is too high to connect a cable on a IIci (see image below). I verified the Graphix card...

Oh they do! I have a IIx with 128 MB in it.

Maybe your SCSI chip trips a little too easily? The cable (or length or wire) provides just enough inductance/capacitance to absorb a slight voltage dip? BTW: /REQ has been a source of trouble for Apple before. (And, you made the first comment on my write-up in this thread)...

When you search for the partial word "scaveng" in the SuperMario source, there are at least 30 references. None of them seem to use the resource fork info. But, maybe Disk First Aid or Norton use it? Maybe it helped them in testing/debugging? Besides the inconsistent hash, I'm bothered by: 1...

Thank you for these answers. It really clears things up. I honestly couldn't see how the SWIM affected memory, but I have been reading that table wrong.

This is more complicated than I thought. However, I think the ability to use Virtual Memory definitely indicates that the Doubler's 68030 MMU is active.

I was cleaning up the basement and ran across this Macintosh. I can't find any documentation on it -- so I am going to try and make some educated guesses on the specifications. Built-in B&W display. One floppy drive (non functioning. jammed?). Pre-ADB keyboard. No arrow keys. I must have lost...

Very interesting. You're saying if I throw in 4x4MB GAL SIMMs into both banks (32 MB total), I will get 16 MB of addressable memory in 32-bit mode (via MODE32) even without a PMMU? And, when I add the PMMU, it can map the other 16 MB to give me 32 MB? So, to test if the Doubler's 68030 PMMU is...

It surprises me that the IIx suffers from needing GAL/PAL memory but the IIcx does not. I always thought of the IIcx as simply a IIx with fewer slots. But, apparently they incorporated some other improvements as well. It appears that 2Mbit EPROMs require 32 pins, whereas 1Mbit EPROMs only need...

Yes. With Mode 32 installed in the System, the Memory Control panel offers the ability to switch to 32-bit. I have the AMMU installed. It seems like the 68030 MMU overrides it. Agreed. I was actually hoping that maybe we could install custom IIsi ROMs with the memory check disabled. Yes. It...

What part# of EPROM (or similar technology) would be needed to replace the Mac II ROMs? It might be worth upgrading the ROMs rather than side-stepping to be able to get the benefit of >8MB of RAM since the Doubler has a PMMU. Anyone interested in making 4 MB or 16 MB SIMMs using the OR-chip...

Oh. Very interesting.