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Also curious how that thing benchmarks against an accelerator with 50MHz and cache - DiiMO or PowerCache

Looks like he has different options for auxiliary power supply boards... the blue one takes a floppy drive power connector, the red one contains a stepdown module to provide power through an external power brick. I was looking into doing something similar but use the usually pretty beefy 12V...

Have you checked the voltages? The power supply might be bogging down with the extra load of an extra accelerator. A lot of Plus accelerators back then came with extra power supplies for that same reason. Either way schematics in case you want to check your accelerator against them: (the...

What's wrong with it? Did it get SE/30 PDS'd like the one I once repaired for @JDW?

On the SE/30 it's done in a similar fashion. The "analog GND" as it's called on the schematics is connected to the main/digital ground through inductors.

I do have one of them. They are not programmable ICs at all. HALs are the mask programmable variant of PALs. No sure if they even contain the the required logic to be read. I don't think they do. But at least all states are clearly visible and only change every clock cycle. L-type combinatorial...

Worth a try, I've got an old programmer that still does all sorts of PALs. If we get one of those thingies my way I can give it a try (and take a look at manually recreating some code if it's locked) Unless porchy wants to take a look, figured that might be easier from a shipping point of view.

Got any other Nubus card you could try in the IIsi? There's a cap on the IIsi adapter which when it's leaking can eat through nearby traces resulting in the Nubus slot not working. Have seen that on two or three adapters now already that needed a trace or two repaired to come back to live.

Did you swap the neck board with the CRT? Smearing can be caused by a bad transistor on the CRT amplifier.

Regarding cracking the PLDs, yes. Partially done with noodling out the schematics and looking into how to route this thing so I won't need an 8 layer board.

Done already... The original is an 8 layer board, I imagine it's no fun at all routing the whole address and data busses through that narrow area on the board between host socket and CPU. Got one of those too. You can swap the crystal for one with 100MHz and it will happily run the CPU at 50MHz.

Yep, you're right, filament is powered right from 12V.

Can't you just cut out the HSYNC signal from the logicboard? No Hsync, no HV and as heating voltage and everything else are received from separate flyback windings it should all be shut off, shouldn't it?

At least they all have consistent mask revisions and matching package identifiers. I haven't seen those correctly matched on fakes yet.

Unfortunately that's as fake as it gets. The chip you've got there is very likely a E31F mask one. You can tell by the package ID on the bottom left... all E31F chips I have seen so far end in -001 just like yours. L88M chips will have -104 there. Nevertheless most if not all E31F chips will...

Just as the readme on github says, this is by far not a tool to "dump" PALs at all. It's more or a just a tool to assist manually rewriting equations to match existing PALs. (no need to say - it's great at that though) So figuring out PALs using DuPAL still takes a lot of time, effort and...

Broken address lines to the ASC are a common issue. I have seen a single broken data line as well but that is way less common. it's not totally impossible that this might as well cause your shutdown woes with 7.5 and above reading back values from the ASC for whatever reason which is going to...

This does already exist: https://github.com/DuPAL-PAL-DUmper Despite the "Dumper" in its name it does not dump anything. If you've just got a PAL and no idea where it was used and don't know what it did in a circuit you'll be having a hard time (that goes for all of the existing PAL "dumping"...

Cap goo leftovers around the sound area of the board. I had the exact same problem on my Portable. As soon as the sound chip was kicked into low power mode by the power manager (aka the 12V supply to the sound chips gets shut down) it started screeching horribly. I desoldered everything from the...

That's because it happens so quickly :P *Sidenote* I did overdo it in the video on purpose, it should be noted this was not going to be a tutorial of any sort. It looked rougher than it actually was. No pad was harmed in the process ;) Someone good at physics should some day calculate how much...