Careful not to get too far into feature creep. I think the motivator behind FPGAing some of the logic functions is because the original chips are NLA, which would allow people with battery-damaged boards to return their machine to life even with the loss of those original chips. My current take so far has been assuming original logic placed onto a new board. In this route the only real improvement available would be to add 72-pin SIMMs or possibly EDO SODIMMs (those could be had in 64MB quantities, so you'd only need two slots for 128MB). I don't know enough about the memory subsystem used here to say whether it would support high-density EDO chips or not. Previously these used 8 16-bit banks of basic or possibly FPM DRAM for its maximum of 128MB; I don't think EDO was introduced until the 72-pin SIMMs. Maybe with the higher-density memory it can use more than 128MB? I don't know what the hard limit is here. Not that I'd probably have a use for more than that in an SE/30. That being said it's probably less expensive to fix an SE/30 board by moving its components to a new board with four 32MB 72-pin SIMMs than it would be to get a replacement original board and find 128MB worth of 30-pin SIMMs.
Guys, it must be possible to convince the Pivot SE/30 Card, that it is connected to a landscape radius pivot monitor at boot time, i.e. displaying something like 864x640 on VGA. I found these two thread with a Radius Pivot IIsi card, indicating, that connecting pins 4 and 10 on the pivot side might do the trick. @Bolle, what do you think, might this work with our SE 30 cards?
Some non-Apple drives don't boot from CD very well. Why this is, exactly, I can't say, but it's true. Maybe something to do with how the drive presents itself to the Mac at boot time or how it responds to queries. I dunno. Anyway you'd have better luck using Sony, Matsushita/Panasonic, or Pioneer drives than most others, at least as far as SCSI drives are concerned (ATA drives were newer and thus (the quality ones at least) were usually less fussy). I'd recommend avoiding other makes than these except possibly Toshiba and even then they're not preferred. TEAC, Nakamichi, Plextor, RICOH, and Yamaha drives are good, but they're often not ideal for trying to boot and, unless you're using a Mac clone, they often won't line up with your drive bezel and/or the eject button will be in the wrong spot. That said, I put an awesome Nakamichi compact 5-disc CDROM changer in my PowerCity/Starmax 4000 and an awesome Pioneer slot-loading DVDROM drive in a highly upgraded UMAX S900. I used D2CD to control the Nak and Toast's CD reader extension with the Pioneer.
Older drives often dislike CD-Rs, and most absolutely despise -RWs, so don't be surprised if your drive won't properly read these.
Because you're using SCSI, check termination. These drives aren't always well-labeled with their proper settings; sometimes the TERMINATOR jumper needs to be ON to enable termination, other times having the jumper ON disables termination, and some others (usually 2x or slower) use internal resistor packs that you have to install/remove manually. You have to check the manual for your specific drive to be sure. Alternatively, if it's the only drive on the bus, you can use a cable terminator if you have doubts (they make internal types too). The point is: termination can cause all kinds of problems, including some you're experiencing, so check this first.
Internally, most of these drives' mechanisms are similar: spindle motor and optical block together on an assembly that goes up and down to secure the disc between the spindle and the (usually magnetic) clamp hub thing. Normally the only problems with the spindle/hub are if the clamp hub breaks off or the friction-enhancer stuff starts to break down and become gooey, leaving a ring of gunk on the center hole of your disc.
As for the optical block, they're also pretty similar between makes, at least basically: lens, lens suspension, focusing coils, focus adjustment potentiometer, maybe a laser diode output adjustment pot, a prism, a laser diode, a pickup, maybe some small ICs, all on an assembly that slides back and forth via a toothed rail and train of cogs and/or a worm gear. Early drives used glass lenses and metal (usually copper) suspension for the lens, but newer cheaper drives use plastic lenses and occasionally plastic suspension. The plastic lenses cloud eventually, and the plastic suspension can sag, both of which cause problems at first and ultimately render the drive unusable. There's no fix for these problems: you have to replace the optical block assembly.
You can try very lightly cleaning the lens with a lint-free swab and 90% iso, with very minimal pressure in a front-to-back manner. Don't swipe more than once or twice without rotating the swab, and don't repeat the cleaning with the same swab or you may scratch the lens with dirt that has adhered to the swab. The front-to-back motion is so that in case you do scratch the lens, it's easier for the pickup to compensate for (side-to-side scratches are more severe because of the rotation of the disc).
If you have a drive that refuses to read any disc even after a cleaning, you can try adjusting the focus pot. This is a fiddly procedure that's meant to be done with specialist equipment with the drive in some sort of service mode, or even at the factory with the optical block removed from the drive entirely, but it can be done just by tweaking the pot one way or the other until the drive tries to read a disc, and then fine-tuning it to where it works reliably. You'll often have to partially disassemble the drive for each adjustment, which adds to the pain, but it can be done with just a power plug; the drive will try to read a disc without being attached to a computer. I've resurrected several Matsushita 4/8x drives doing this, even getting them to reliably read CD-Rs where they wouldn't even attempt to read any disc at all beforehand.
If the drive was used in an extremely dusty environment, some fine dust may have entered the depths of the optical block under the lens, which will cause problems. It's not recommended to use HFC-based duster to clean this out because that stuff can fog the optical components (same reason it's not recommended for use with cameras). Using very low pressure compressed (and filtered) air may help but sometimes, especially if a smoker was involved, it won't come clean with air pressure alone. You can try to disassemble the optical block and clean everything by hand, but you're on your own for figuring out how to do so; I don't have any suggestions and many of them were glued together.
Good point, I play with the building blocks at hand.
I was under the impression that much of the interest in bringing the SE/30 design back to life was to condense a large part of its known logic into FPGA, CPLD or other magical little black boxes. In that scenario there's PCB real estate available to build a lot more function into the board, or stick a smaller board into curious spaces.
Why not slather a full 128MB of TSOP or the like on the bottom/top of the PCB eschewing memory connectors of any kind. Why limit the dream to the thruhole state of mind?
SIMMs 4-6 can probably be replaced on the SE/30's logic board with 72-pin sockets with minimal effort: delete SIMMs 1, 2, 7, and 8, then scooch some of the discrete chips between the RAM and the PDS around a little, either closer together or reposition in the empty space above/below the new RAM sockets.
Alternatively, perhaps rotate the new 72-pin sockets 90 degrees instead? I don't have measurements handy but that may work without reorganizing any of the other board components.
It appears the slanted sockets need about 50% more board space than the vertical type sockets though. If you're going to be spending a bunch of money printing a custom circuit board, you may as well buy newer low chip count/shorter SIMMs rather than try to squeeze in big old SIMMs. I know there were some 4-chip (TSOP style I think) 32MB 72-pin SIMMs but I think they were EDO, so as long as the SE/30's memory subsystem can use them (I know FPM and EDO features are harmlessly ignored on most Macs) they would be a good choice.