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Can you provide external power to your Blue SCSI, so it's not drawing power from the Portable? That might be an interesting test.

I'll be interested to see what you find. A friend of mine is experiencing similar problems with his recapped Portable. It refused to boot from SCSI, would usually boot from floppy but then immediately crash with a variety of Sad Mac codes. He replaced the hybrid module and also added a battery...

I'm curious, did you look at the first couple of sectors and could you tell what was wrong with them? When I was playing with this recently, it seemed about 50/50 whether a "CD-ROM image" from Macintosh Garden would be a device image with a partition map, or just an HFS volume image. Yes. My...

All the normal Mac-to-VGA features are working well, but getting to 100% on composite sync splitting is proving to be very hard. It works for most combinations of video sources and monitors, but not all of them, and code changes that fix one combination may break another. When a monitor won't...

The latest Floppy Emu firmware does have CD emulation, but you'd need an HD20-capable Mac, and it's like 1x CD-ROM speeds. Considering the tests you did in your second post, I kind of doubt this is a problem with the Startup Disk or driver. It seems more like the SCSI2SD is not ready or does...

Is it just the +12V supply that's not working? I don't think Blue SCSI actually uses the +12V supply. So while the absence of +12 is a concern, it's probably not the reason you can't boot from Blue SCSI.

@olePigeon Full page displays should be OK, I think, but I'd need some help with testing 3rd-party FPD video cards. Full page displays might not be the best example though, since even with proper sync signals and a VGA adapter, most modern monitors won't be able to display a 640x870 image...

Well, this composite-splitter VGA adapter effort is still ongoing. It was 95 percent working, but it was full of special case code for specific video resolutions, and I wasn't happy with it. So I went back to the drawing board with a different approach. I will spare you most of the boring...

That is an impressively big mess o' wires! :) Nice work on the hardware!

I'm a little surprised you aren't seeing longer run times with the rebuilt batteries. Do you know the specs for how the original batteries performed?

For a 68K on-computer solution, I think you'll need to explore the path that @s_pupp mentioned. Use a tool (maybe FEdit) or a low-level disk copy tool like Copy II Mac to read every sector on the disk. One or more sectors will probably fail to read, but with some manual effort you may be able to...

Yeah, I'd be very interested to know the chemistry behind "retrobright will ruin your plastics". I'm not saying it's wrong, but I've never heard an explanation why this should be true. As I vaguely recall, retrobright helps remove some boron that was originally added to the plastic as a fire...

You're right. I was thinking more about the earlier models. SE/30's and Classics especially could be a source of CRTs from Macs with dead logic boards.

I like the optimism but I'm not sure that follows. The 9 inch compact Macs mostly don't have the type of capacitors that leak or the type of batteries that explode. But ignoring that, if somebody did have a compact Mac with an irreparably-damaged logic board, how likely would they be to keep it...

They remind me a little of the Car Talk radio show, or the tv show American Choppers. Each episode is a technical challenge. What are the symptoms? What are the requirements? How can you break down the problem and isolate possible solutions? What kinds of practical techniques are used in...

This has become a project where the closer it gets to finished, the slower the progress moves. I'm discovering that software-generated sync signals are easy to get mostly right. I have an ever-expanding test matrix of video sources, video resolutions, and monitors, and whenever I make a little...

The 9 inch compact Macs have mostly proven to be amazingly reliable, even as we approach the Mac's 40th birthday. But I'm hearing about more CRT problems than I used to, particularly with the flyback transformer, and I gather there's no new source for a compatible flyback replacement. Is it just...

From what I've seen (not just in Apple's schematics) the voltage rating of a capacitor is often omitted when the capacitance is roughly 0.1 uF or less. I've always interpreted this as a "don't worry about it" message from the designer. But if you want to be extra sure, do as David suggests and...

That's the wackiest thing I've heard in a long time. Junior engineer: We need to add a 12V supply to this card but all the I/O connector pins are already used. Senior engineer: Hold my beer, I've got this.

Are you planning to remove those upgrades and revert to a stock 512K config? With the upgrades it's essentially a Mac Plus, which you already have, no?