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As an overall note, those pictures are very blurry. It's hard to see details in them. Just to restate, you have tried a BlueSCSI V2, a DB25 BlueSCSI (which version? V1 or V2?), and a Zulu and none of them work? There could be several things going on: * this might be trying to use custom...

I've been thinking about something that could work with the video out port on the Portable. I keep trying to move on to things other than the Portable but it keeps pulling me back (yet another Portable project is underway now at the schematic stage). The VideoMacPack is particularly weird, the...

Been working on an update to the BlueSCSI Desktop board for awhile, and it's not quite done yet. But figured I'd clue you all in: Initiator Mode This allows BlueSCSI V2 to in-place take byte-level images of original SCSI drives without needing the actual host machine. It could also lead to...

Contest submissions are closed (closed a few days ago actually). The judges are deliberating now.

Please note that there were no board meetings in June or July due to a lot of scheduling conflicts. August 26, 2023 Board Meeting Attendance: Kai Robinson, Christian (fogWraith), Jacob (Androda), Eric (eric), Ron (Ron’s Computer Videos), Justin (jdmcs) Absent: Bruce (Branchus), Josh (Drake)...

Looks like that picture of old and new DB25 side by side has the prototype version of the smaller DB25, oops. The version I pushed to GitHub (and which the sellers will have) includes an activity LED by the microSD slot.

Adapters do exist for using a BlueSCSI with the Portable, on my site. These ones *only* work with BlueSCSI though, and do not present a Molex connector for use with a different drive style.

Yeah, that's the paradox you as the buyer will find yourself in. As a "best practice" I would say you should send the seller a request for lots of pictures. If they are unwilling to open the battery bay, remove any batteries which are present, and take photographs of it from various angles...

1: The Backlit Portable has a similar circuit to the "hybrid", just directly on the motherboard instead of on a dedicated separate PCB. It's very vulnerable to capacitor leakage, as the keyboard/trackball connector next to it has a few capacitors right there. @techknight would know failure...

This is basically what I expected. The RP2040 microcontroller designers made the rather strange design decision to put all IO pins into "pull down" mode at chip startup. This means that the control line (not data) transceivers pull lines low until execution enters our userland code out of the...

That's pretty cool, free CPU accelerator from simply running the expansion RAM faster. Maybe I can stick that into the CPLD somehow, another pin for great acceleration...

In order to assist the BlueSCSI sellers in testing their devices, I created this semi-monstrosity known as either the SCSItron or BlinkyTester or something along those lines. It's the SCSI-est thing I've ever made. It consists of a standard 50 pin SCSI input connector, and presents a bunch of...

The RAM card listing in my shop has been updated with a dropdown. Basic: No switches, always 7 megs of RAM (Except M5126, that one sees 3 without a jumper wire) Switchable: Reworked boards similar to the above picture, until I run out of these and then all in the future will have the switches by...

OK, the mod boards arrived and they look pretty nice. 4 wires to points on the card and it presents the four RAM size modes listed before.

Assuming the issue is caused entirely by the size of the expansion card, yes. It should have the exact same problem. Or in other words, the Portable seems to slow down with expansion RAM cards above a certain size due to what is either a hardware or software bug in the Portable itself.

Mod boards have shipped, once those arrive I'll test the updated firmware some more and update the listing again. I already changed it to point at this thread for clarity on the speed decrease. Likely will have two options after testing, "Plain" and "Switchable". Then going forward, future...

Yeah, no need to rework the whole PCB when there are only a few pins that need tweaking. Future revisions of the RAM card (if they ever sell out) will have the switches by default.

This design is a "modboard", so it would be glued to the main PCB and then it's just four jumper wires. There's no need to order new "full PCBs" since I can just reprogram the CPLD and use a few more of its input pins as configuration.

I have started work on an alternate firmware and switch-mod-PCB for the RAM card. This will allow switching between the following modes: * M5120 "Low RAM" (4MB on expansion card) * M5120 "High RAM" (7MB on expansion card) * M5126 "Low RAM" (3MB on expansion card) * M5126 "High RAM" (7 MB on...

PDS probably doesn't have the perf penalty, because a PDS expansion card would be able to trigger EXT.DTACK independently of the glue logic.