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So, I've worked on a couple of these, and they have a few failure points/common problems from what I've seen. Couple of questions, though: Does the green LED power on? You hear it energizing - is there neck glow? If it sounds like it's powering up, that's a good sign. Unfortunately, you'll...

Alright, here's what I've got so far; this should be the near final design for V1.0 of the Mega. I'm considering adding an optoisolator, and you'll see why in a sec. I need to do some more breadboard testing now that I have the stepper working, but I'm pleased with how things have progressed so...

Yep - sorry for the confusion. You can either put the SD card where the DB19 would normally go (which makes it easy to get to, but means you can't use it in a daisy chain) or you can put the SD slot inside the case and transplant the DB19 connector from your old HD20 to this and use it in a...

I should be ordering the PCBs for the Mega this weekend to get them tested. They have minimal changes from the original design (they're mostly adapted to the HD20 controller card's form factor is all) so they should just work. Here's the preview which is now slightly out of date - I'll update...

They have arrived... ...and it's a perfect fit in the card cage. Should have one assembled by this weekend; wish me luck - this thing has over a thousand pads to solder, lol.

Quick update for anyone following. Version 1.0 of the PCB is going to get a second set of eyes doing one last sweep and then it's off to fabrication. With the help of the person working on the I/O card, we (they, really) were able to figure out how the layer indicator transparency needed to...

Well, almost two months later and here we are: Not visible are the two inner layers form +5V and ground (well, DGND). This is effectively 100% complete, but I'm trying to get one last piece of cosmetic flair to work before calling it done. The software I'm working with (EasyEDA) does not...

Thanks - I'll take any luck I can get, lol. To answer your question: yes - you're spot on the money! The scan may not show it very well, but on the top-right of the rear of the PCB is a very faint (almost to the point being gone) silkscreen area which reads "MADE IN SINGAPORE". Also, I've...

Excellent find! That was a very informative read - thanks for posting! :)

Going to have to take a few days of after-hours progress off on this to rapidly install a drainage system for my yard before round two of heavy rain hits the DFW region this coming weekend. Spent yesterday morning digging a trench in my back yard to prevent my shop from flooding, so we're just...

Okay, small update... well, less an update and more just providing some reference images. They're a bit large, but they're a fraction the size of their TIFF parents. These are unfortunately only 400dpi; I have access to another large format scanner that can go up to 12800dpi (lol, each side of...

Mine has them as well, and just like yours they are spliced in manually. Alex's must have been an earlier revision.

Huh - TIL. That's pretty awesome! What model InFocus did you use?

Heh, not an "optional" board, unfortunately - the Lisa backplane just pipes the same TTL video signal that goes to the CRT out to an RCA jack for connection to a TTL-capable display.

Jokes aside, I'm wondering if those were just to prevent wonky power situations from damaging the parallel interface logic... That looks like one of Alex's boards; I'll reach out and see. They may not be necessary, but I don't know that I'd run without them.

On to unfortunately bigger things! Next up is the CPU card and, boy oh boy, is this going to suck. First and foremost, a huge thank you to user jamesdenton over at LisaList for providing me with a busted CPU card, as he's allowed me to depopulate it and scan it for reference for this task. I...

Bit of an update. The preliminary draft of the 512K card is done and ready for review. This is the two layer version; I'll be working on the four-layer soon, but wanted to put the two layer board to paper first. I want to sleep on it and look over it one more time in the morning before pushing...

You know, I saw a post about that in a local (DFW) retro computer group and just figured it was some Apple II thing, based on the color scheme. Guess I should have looked a little closer, lol.

As part of my ongoing efforts to resurrect my Lisa 2, I've stepped back to work on a much broader goal: the reproduction of the Lisa's card stack in full. While the motherboard and I/O board have been reproduced, they are either no longer in production and impossible to find (in the case of the...

Small preview of where things are headed; this is just a rough draft, so don't worry too much about some of the positioning and silkscreen issues. More to come later this week; stay tuned...