MOS8_030

Here's a thread that shows the empty socket. The CPU has to carefully come straight up to avoid bending/breaking any pins. Why to you want to remove the CPU?

That's fan they used because that's the fan they had.

Find a 16mhz 68881/82 for that empty socket!

That's probably the correct date. Check the dates on some of the other caps. If your system isn't original then there's no telling when that board was installed. Certainly Apple provided replacement parts for Plus's for several years after they officially stopped production. They may have still been selling Plus upgrade kits in '92, I don't know. (Apple also supplied re-worked boards as warranty/repair replacements.) If you pull the board completely out and check the soldering on the back you can usually tell if the board has been re-worked. There may also be a date penciled on the motherboard there next to the Apple Computer name. It would be the same format. (that white square to the left in your photo.)

Maybe. I would check the part numbers to start. iFixit might have some info as well.

It's stock, just a later axial version. Look for a date code on it. Usually it's year/work week or vice versa. Here's another like yours.

Which version of HD SC Setup did you use? Sounds like the SCSI driver that the Plus needs to boot isn't being copied to the disk during setup. You might try the early version that comes with System 6. (patched of course) I forget the version number. Also, some early Plus's have buggy ROMS regarding SCSI. (Although this is probably not the problem.) Also the System folder on the HD needs to be "blessed".

Howdy! I believe those Atari disks are only 800K. They should work, but new HD disks would be better. New floppy disks are available much cheaper from places like Amazon or other retailers.

None that I have found, and I looked pretty hard a few years back, otherwise I would have repaired mine then. Reading around no one seems to have pin pointed a common failure mode, of if they have they haven't shared that info, unless something new has been posted in the last couple of years. You can do the ATX mod to the QS too. But it's a bit more complicated. http://atxg4.com/quicksilver.html

ATX extension cable so I could route the wires behind the optical drives like the original PS. I have a full-length GF Ti4600. With a shorter card the extension may not have been necessary. https://www.amazon.com/Cable-Matters-Motherboard-Power-Extension/dp/B01DV1Z66C/

Yeah, it was actually pretty simple after I surrendered and bought the Molex tool. I hate having to buy a tool for a single job but really it was necessary. On one of the pages about the ATX conversion I saw a warning about some systems having problems with deep sleep. I haven't seen that or any issues with my system. I suppose heat could be a problem if I ran the machine really hard but I only use the system every few days mostly for iTunes or browsing the web.

Here's how I mounted mine. I used a couple of sheet metal screws through the top. (under the plastic of course.) I first tried some double-sided foam tape but it wouldn't hold long term. These pictures were taken before I was completely finished. I also had to get an ATX extension cable to be able route the wires behind the optical drives. The power cord routes out through the original plug hole in the back. I also did have to invest in a Molex extraction tool. I tried other methods to remove the pins but finally gave in. I think I paid about $16 for mine, I got it online somewhere.

There's a database for 128K, 512K, and Plus's here: http://www.mac128.com/Mac128/m0001

Here ya' go. http://atxg4.com/mdd.html After the second power supply in my MDD died I finally just installed an ATX PS. It's been working fine for a couple of years now.

When I was volunteering a Goodwill back in the late '90's they were awash in compact Macs. Pallet loads (heck, truckloads!) came in from many of the high-tech companies in the area as well as from individuals. Initially they tried to sell 128's & 512's for ~$10 each then $5 but no one was buying. At some point anything less than a Plus was just sent for recycling. (or the dumpster.) By the time the iMacs were introduced pretty much anything less than a IIci became worthless. There were so many 128's & 512's some of guys back in the warehouse set them up as pins and used an old bowling ball to knock them down!