I spent a long time this weekend troubleshooting a Commodore VIC1541 disk drive only to have it spontaneously start working. I cleaned the belt, de-oxidized the connectors, re-flowed some suspicious looking solder joints, and tried a variety of different disks. Its working reliably now though and I’m able to use it as a bridge between the internet and the C64 via a ZoomFloppy. The ZoomFloppy connects the 1541 to a PC via USB so that disk images can be written and then later loaded on the C64.
Following-up on the Apple IIc computer refresh, I recently cleaned up the IIc’s monitor. Disassembly of CRTs can be dangerous due to high voltages, but at the point of disassembly it had been unplugged for a few weeks and I made sure to discharge the tube and capacitors as soon as I could. From there it was just a matter of cleaning the plastics, using a magic eraser for scuffs, and de-yellowing. The de-yellowing is accomplished by covering the surfaces in peroxide, putting the parts in bags, and then submerging those bags in a bath of hot water kept warm by a sous vide heater.
A few of the potentiometers for size/position/brightness were dirty, causing the picture to cut out unless adjusted perfectly. This was resolved by spraying some contact cleaner under the knobs and exercising them.
Since moving, the home office area has taken a back seat to other projects. Although it’s been fully functional, there were many unopened boxes filled with books/computers/etc. This weekend we started the process of unpacking and organizing the office stuff with the goal of understanding what kind of storage space and desk space is needed. I’ll use this info to design/build cabinets, hopefully some time in the near future.
One of the boxes contained an Apple IIc. It powered on OK, but the video signal was flaky. The video connector felt a little loose, so I opened it up and found that the connector design relied on a crimped connection that had worked loose over time. With a very hot soldering iron I was able to heat the crimped connection and flow solder into the joint.
This fixed the video problem from the IIc side, but on the monitor side the brightness knob has to be set just right or the picture scrambles. I suspect the brightness potentiometer has oxidized everywhere except where the wiper was sitting for the last 20yrs. If this is the case, then I should be able to fix the monitor by just spending some time turning the adjustment knobs back and forth until it clears up. Either way I’ll be disassembling both the monitor and the IIc (again) to fully clean them and reverse the yellowing of the plastics; I can replace the potentiometer at that time if needed.
I’m planning to set aside a corner of the office for the retro computers (Apple IIc, Macintosh Plus, Commodore 64). As I unpack these I’ll post more details on getting them cleaned up and working again.