Okay, so more research is never a bad thing.Â I dug around a little and came across a copy of Sun Remarketingâs Do-It-Yourself Guide for the Apple III.Â You can download it in PDF from 1000bitâs documentation archive here, and if you ever have to do any hardware troubleshooting on a pre-âPlusâ version of an Apple III, I highly recommended consulting this guide.
Serial #018052, which Iâd decided to try to bring back to life first, is one of the original 12V 128K Apple III units, released before the recall and re-issue of the âenhancedâ 5V Apple III.Â Note that the 5V isnât an Apple III Plus.Â Those came later, after a second recall and resdesign.Â Apparently the III Plus was only on the market for a short time, the damage in the publicâs perception of anything with an Apple III label having already been done, so the Plus sold in very low numbers and today is a much rarer commodity and more highly desired by collectors.
At any rate, I learned that serial #050756 is also a 12V unit, so I could hopefully scavenge for working parts.Â Serial #051780 is a 5V machine, and for my purposes, not of much use.
I ran the in-built memory diagnostic mentioned in Sunâs guide and discovered that two of the RAM chips on the Apple III Main Memory board were bad.
Bad RAM chips, as indicated by inverse blocks in the memory map
Crossing my fingers, I borrowed two chips from 050âs board andâ¦Â Success!
A healthy RAM board passes the diagnostic
As an aside, I also discovered that the memory board in 050 was installed backward and may have been at least partially behind the unitâs earlier complete boot failure.Â Note to self, getting 050 up and running again may not be as daunting as Iâd thoughtâ¦
Now to address the 081âs floppy issue.Â Again, an easier fix than Iâd believed.Â The floppy cable was plugged into the wrong port on the drive.Â Moving it to the correct port brought it back to life, at least to the point where it tries to read a disk at power on.Â It may have other issues (timing is apparently a big one with these drives), but until I fire up ADTPro and transfer over some disk images to real floppies, I wonât know.
The drive tends work better when it has been properly cabled.
Finally, thereâs the issue of the case.Â This is mostly a cosmetic thing and one Iâm not as worried about, though I am looking forward to experimenting with Retrobrite.Â The cases I havenât been too badly abused, suffering only light scratching, dirt and the requisite yellowing that comes with age.Â I picked what I thought was the best of the three and did a little basic cleaning with some 409 and paper towels.Â The final result?Â Not too bad, I think.
Not as pretty as the day it was manufactured, but closer than it was a few days ago.
Still to do: dig out the Apple Monitor /// thatâs supposed to go with this thing; whip up a batch of Retrobrite and get to transferring disk images.
Given the condition of 050, that will probably be my next Apple III project.Â Tracking down the parts needed will likely be the hardest task.Â Anyone have a good source for Apple III keycaps and 12V RAM chips?