2023-08-13
My first computer was an Apple II that I bought with money I earned from working at Baskin Robbins back in 1980. It was my first experience with computers and was very early on in life of personal computers, exciting times. I didn't get a degree in Computer Science, mine was in Physics but I ended up spending my career in software development and devops. Even 40 years later it is an amazing computer, it allows you to understand computer architecture at a base level. It is also a very sentimental for me since it launched a lifetime of learning on software and hardware.
Unfortunately, I ended up selling the Apple II I had back in 2006 but I've reacquired an Apple II+ off ebay along with a 9 inch monitor like I had back in the 80s. The Apple II+ worked well right off the bat except the safety capacitor burned up, I got a recap kit for the power supply from Apple II power supply capacitor kit. It was still having issues so I went ahead and got a complete modern replacement Apple II replacement power supply, now everything works well on the Apple II.
The Monitor is from Taiwan and is period accurate for the Apple II, in fact it is very close if not the exact monitor I had back then. These green screen monochrome monitors were fairly cheap and worked well. The model number is EV-9031 but I've had no luck in finding a service manual for this model.
The initial issue I had was that I could not sync to the video at all. I thought this might be because the monitor could be a PAL version and not NTSC, this was because it had a euro style plug. I didn't have anything else to test the composite output of the Apple II at the time, so I went on the assumption that the electrolytic capacitors had gone bad. I did not see swelling, but there was some residue on the PCB and using an ESR (equivalent series resistance) meter some were showing out of spec.
So I went about replacing the electrolytics, I started with the larger ones on the power supply but ended up replacing them all. Here is the full list in case someone has the same monitor:
I also replace the vertical deflection IC at the same time. The result was better but not perfect as seen below.