Since getting my Apple //c in June 1984, I have been a huge fan of this machines, and I regularly browse Craigslist for machines to rescue. I now have 6 machines of various kinds in my garage, maybe it is time to admit that I have an issue.
Over the last 5 years, I managed to locally find a couple of original Apple IIs, great machines, but both were upgraded to Applesoft roms. Back in 1979, I would have done the same, upgrade to a newer firmware, get new features. I do this with my phone, my car, whatever can be upgraded. But 30 years later I am trying to get things in their original state.
This means re-installing the original Integer roms. For many hardware fanatics, this is fairly easy, but I am not one of them :) I had both machines open on my workbench swapping roms right and left, but could not get them to work, various errors, no boot. Removing chips from the board with a screwdriver, installing new ones, testing, back to step 1.
Browsing the II Enthusiasts group on Facebook, I got in touch with John who lives close by. He agreed to help me, so I went to see him with my machines, and a bunch of roms to try out. This ended up being a great afternoon, I met a great guy, so knowledgeable of both hardware and software.
|Opening Apple II and starting the tests|
|Home made board to test main logic steps|
The machine would boot to a garbage screen, but never complete the process. John used his own board that checks every important chip for i/o, voltage.
|Removing each chip and single testing them. Found 2 4116 ram chips in the process|
|Magnifying glass to look at the board and traces|
After checking every chip (replacing 2), the machine is still not booting, time to dig deeper. John opened Understanding the Apple II. This book is a collector item, I had one at some point. It was nice to see the actual value of the book at work, it is not only an expensive collector item, it is also a very useful book.
|Understanding the Apple II|
|Still not booting|
Finally the error was diagnosed, My screwdriver skills cut traces on the board. Not surprising I admit.
This means it is getting better, I learned. And it is finally booting.
My fixed Apple II running Karateka