My 1571 disk drive throws some weird errors. In this series of three videos, I attempt to repair it…
Very occasionally the drive works. Mostly it throws a “51 Overflow in Record” error when it attempts to read anything (directory, programs, data…). This is weird because that’s a write error! Yet it’s not writing…
In part 1, I perform essential maintenance – strip the drive down, clean it, and replace the electrolytic capacitors. A good general overhaul in fact Does this fix it? Well, obviously not, or it wouldn’t be a three part series!
In part 2 of my 1571 disk drive repair series, I get down to some serious debugging, breaking out schematics, manuals, service and troubleshooting guides. I put the scope on it, and yes, I find the problem. At least, I find A problem. Because some of the logic outputs are definitely screwy. Sometimes. Maybe there are faulty ICs, but all the chips are soldered in, so they will need to be unsoldered…
In part 3 of my 1571 disk drive repair series, I continue with the serious debugging. My eprom programmer has the ability to test logic chips. Some chips anyway. I put the chips that gave the faulty readings into the tester, and – surprise! – they all pass. Every chip passes. The chips that I can’t test can be swapped with known good ones (some bought especially), and yet the problem persists.
But then by sheer coincidence I decide to… No. Watch the video and find out, because you will be amazed at the answer.