FYI.... status update....
Found an issue with the modified circuit board I made. I had the "ACK" and "ACT" lines swapped. Oops! This was easy enough to fix with a cut/jump on the board though.
I was able to get the RaSCSI software running on a Raspberry Pi 4. My Quadra is able to see the virtual hard disk I created, as well as format, read and write to it. I ran a quick benchmark, and the performance seems to be on par with my SCSI2SD v5.
My current sticking point is with CD-ROMs. Using various SCSI tools, the Mac can see that there is a drive present at the correct SCSI ID, but it hasn't detected any of the images that i have "Inserted". So, I'm going to keep working that.
In the next few days, I'm hoping to run some benchmarks comparing the different versions of Rasperry Pis, and maybe on some different Mac models. But first, I'm trying to get the CD-ROM functionality working.
Ok thanks. I will give that one a try. I just bought a Macintosh Portable battery from that seller.
On a side note, I picked up this Macintosh Portable as not working, for cheap. When I got it, it looked brand new. The space bar is the same color as the other keys. No dirt at all inside or on the feet. I thought I would just try the new battery not expecting much and to my surprise it booted up just fine.
I'm pretty sure the board has not been recapped, but is likely pretty clean as I don't think this machine was used. My intention was to use this for writing because I love the keyboard, but it is in such good shape I feel like maybe I should not.
My question: Should I just preserve it like it is, maybe find one more beat up to use? If I use it maybe the board will go out or something or I will in some way damage it. This is my first vintage Mac aside from a G4 Cube.
I recapped the power supply, and with a bit of adjustment, got 5.01v and 11.93v.
9/10 startups, I get nothing, but once after ~10 seconds, I get a raster for a second or two (with a mouse cursor!), followed by the zigzag pattern. No bong regardless.
I guess the option of replacing the power supply with a modern one is still on the table, though I don't know if I'm quite ready for that - they seem a little expensive, and I don't know if I have the skill set to choose an appropriate one (the ones others have used tend to not be available).
In case the issue is the yoke, I ordered a new CRT from the same seller Michael_b posted. At the time, I thought I remembered that the CRTs were all compatible across compact macs, but more recently, I came across some material that indicates that while the CRTs are all compatable, the yokes are not, and generally the yokes are kept across CRT replacements.
Once I receive the CRT, is there any easy way to tell if the yokes are compatible?
I take it that switching the CRTs but keeping the yoke wouldn't help if the yoke truly is dead. I actually wouldn't mind swapping the CRT anyway, since mine has a dead spot in the center, but the yoke seems pretty complicated and I'm not sure I want to risk breaking it further for a single dead pixel.
I finally received my analog board. At this point, I would try swapping out the T2 (other than that, I think I've run out of things to replace), but unfortunately, the clip on the anode is missing:
I'm kinda stumped on this one. If I really thought the T2 was the problem, I would just splice my broken T2's cable on to this one, but I don't want to do that and risk breaking a good transformer for a bad one. I guess if I could get the cap off the wire, I could right up some kind of clip, but this seems like the kind of thing that shouldn't be jury-rigged, what with the high voltage and all.
Thanks again, everyone!