Well I jumped the gun on that one. I was using the default emulation mode. I've changed the firmware and booted in to 6.0.8 from the HD20 emulator. Huzzah!
Alright! Troubleshooting progressing!
Floppy Emu arrived. It does the same thing as the floppy drive and hard drive when trying to boot - Happy Mac then back to X. Still won't boot.
I got an error on one attempt that gave Sad Mac 0F0002.
This is after replacing the old 1MB of RAM with 4MB...
I got free shipping- probably went over a minimum order amount.
The capacitors I received were RIFA branded, and were drop in replacements.
If you're near Melbourne I can lend a hand. I've just done all this for the first time myself (discharging a CRT, replacing capacitors, etc.).
I used these components to re-cap my international board. The only irksome thing is I used radial capacitors in place of axial, as they aren't easy to find in stock.
https://au.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=80ed9d1127
Note that the 4700pF capacitors are on backorder now.
I know - I had no intention of opening the drive. Unfortunately whoever designed the drive decided to have a washer and nut inside the drive which falls loose when you remove the stepper motor. If I knew that was going to happen, I would have just added more and more oil to the outside bearing...
I lied. Opened up the drive again because it once more stopped working.
Removed the stepper motor and *oops* the top two bolts were held in using washers and bolts INSIDE THE DRIVE! Eek. So I had to remove the cover and fish them out, then put them back in place.
The inner bearing of the...
Ah! Ta. I opened up the hard drive enclosure and added oil to the stepper motor - after a lot of power cycling it is mostly consistently passing the self test.
Although, it's still not booting.
Will have to wait until the floppy emu arrives before further troubleshooting.
Put the new RAM in today, but we're still unable to boot.
Coincidentally, the hard drive started working for the first time. It is horrifically loud - so I am assuming it has seized and only just became free enough to spin up.
When the HDD wasn't working, it would show a communication light...
Tried to adjust the home position, but no matter what I did the disk wouldn't boot after the 'happy mac' screen. I was adjusting as best I could in 0.02mm increments using vernier calipers.
Adjusted the rotation of the worm drive motor. Still couldn't find a sweet spot to get the computer to...
So, yeah, it's working now.
I remembered I had some 1.44MB disks in the garage. I didn't think there'd be any harm putting them in the Plus.
Chucked it in, and you can hear the drive trying to read the disk. It spits it out. So I put the Mac disk in, and still no luck. Tried the 1.44MB disk...
Ah! It does spin. I left the drive in place, and put a skewer through the front to depress the switch. It makes an abrupt digital sound like 'DE!' when it starts spinning, and again when it stops to eject the disk. I couldn't hear it previously when putting the disk in, because the drive drops...
I can't hear the disk spinning at all. It's not jammed, because I can spin the drive when it's removed from the computer.
All three RIFA capacitors were replaced (with new RIFA capacitors).
Unfortunately this is my only Macintosh, and only disk drive. I assume the easiest thing to do is buy one of the SCSI SD card readers so I can install a known working OS.