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Oh definitely - if the computer thinks there's a display attached, the card probably isn't doing monitor detection, so it'll be outputting a valid video signal even with nothing connected. You'll be looking for a very 'analogue-looking' signal on the R, G and B pins that repeats every 16 or so...

The Bt458 RAMDAC on that card supports 8-bit RGB output, so it wouldn't surprise me if it was a colour card. There does seem to be a de-facto standard for analogue RGB video on a DE9 connector, based on the pinout of the IBM Professional Graphics Controller - the same pinout shows up on Acorn...

That chip looks to be a resistor-capacitor network of some sort rather than a logic IC, probably providing termination for a bus or something rather than a logic function. It would be trivial to identify a replacement part (or even fabricate an equivalent from scratch), if its properties are...

That certainly is a contraption, I love it! A signal integrity issue would not surprise me; I was having bizarre display corruption issues with a video card attached to the pass-through slot on mine, and it turned out to be ringing on the C16M clock line upsetting the video controller chip. I'm...

Hooray! Glad that's all it ended up being! If you don't mind, would you be able to run Helios LanTest and let me know what your read and write performance looks like? Just trying to gather more performance data for various machines. Thanks! That's exactly what I was aiming for with the...

I've had a chance to sit down and play with my logic analyzer tonight, and of course now I can't reproduce the issues that I was having with the card in my IIfx - it works just fine, I think I might have just forgotten to change the slot-ID jumpers when I said it wasn't working. Oops! Looking...

New hardware project: an adapter to connect an HP logic analyzer directly to the PDS slot of an SE/30. Mostly just built it out of curiosity, but it could be a powerful tool for troubleshooting faulty machines or developing new hardware. Expect a writeup soon :)

This is extremely cool! I'm not really familiar with the internals of the 512 to review your design in detail, but looking at your notes and the reasoning behind them, it seems like a sound idea to me. I'll be following this with great interest!

Does it work if you put the original ROMs back in? If so, then my guess would be either that you've got a shorted or missing trace somewhere on your ROM board, or your flash chips or the data that you're programming them with are bad. As a start, I'd recommend cross-checking every pin's...

Actually, that screenshot of the manual reminds me of something - there's a switch internal to the headphone jack that is supposed to disable the internal speaker when something is plugged into it. It's not unheard of for these switches to get dirty and prevent the internal speaker from working...

Did you remember to plug the 2-pin speaker connector back in when you put it back together? It's easy to miss, especially if the cable has fallen back into the upper part of the case. As far as getting the case to close up, mine is a little bit touchy about that too. Make sure that the...

Another thing to check: does poking at the card's address space in MacsBug give you a bus error, or does it return data? There should be 24k of RAM starting at the card base address, and read-write registers at base+7e00 to base+7eff.

oh no! That's odd - I sourced all my parts from Digikey and hand-assembled them rather than using JLC, but the parts I used programmed without any issues, so presumably they had the ID that the SVF file was expecting. As a basic sanity check, with that SVF, pin 34 of the CPLD (brought out to...

🤦‍♂️ my bad. I've only really done hardware-poking on SCSI machines. But yeah, agreed, first thing to try would be to pull the hard drive out and see if the error persists.

Yeah, 0000000F 00000001 means that it got a bus error during early startup; a misbehaving hard drive hanging up the SCSI bus (and in turn making the SCSI controller hang up the processor bus) could be a potential cause there.

^ yeah, good point. And while we're on the topic of floppy drives, make sure that the disk is properly seating on the spindle when it's inserted. When I cleaned the drive in my IIfx, I somehow managed to mess something up that caused the loading mechanism to hang up partway. It would accept and...

Congratulations on finding yourself a project! Sounds like you've done some solid troubleshooting so far. Take all of what I'm about to say with a grain of salt since I've never experienced this particular problem before, but being decently familiar with the SE/30 hardware and having poked...

The analogue board and power supply are common to the SE, so if they do turn out to be bad, that's a cheaper option to use as a parts donor. Building a reloaded board isn't a task to be taken lightly (or cheaply), but if you can solder and have decent electronics troubleshooting skills (or at...

I actually recently discovered that the current hardware/gateware revision *doesn't* seem to work properly in my IIfx - it was only the early GAL-based version that I'd tested on there. I haven't had a chance to dive into it properly, but I've built up an interposer board that will let me look...