Recently, I emailed a friend of mine about an Apple II+ that I remembered he had a while back. He still had it and he was not sure it even worked. Jason is the most experienced vintage Macintosh restoration technician that I have ever met. If it was part of the Macintosh family, he has seen it, repaired it, restored it, sold it, and probably gotten it back again. But he has never gotten into restoring the Apple II line of computers. He told me that if I wanted it, to come and get it. So I took a trip to see Jason and pick up the plus. I brought him a working 1.25GHz iMac G4 that I did not intend to keep. We talked a bit, caught up on each others adventures, and I bought a few other Macintosh parts from him before heading out.
I got the II+ home and opened it up to take an inventory and evaluate the status of the computer: It had a 16k language card, a parallel interface card, and a Disk ][ controller in it. I pulled the CPU and checked the revision – it was rev4. All the ICs were there, there was no visible damage on the main board at all. All key caps and switches were there and seemed to work. The computer looked very clean. When I powered it on, the screen would fill with question marks (?) for every visible character space and that was it. After a few I/O cycles of the power switch, it finally came to life. I played around with it for a bit, testing keys and writing some AppleSoft Basic code, and then it froze, and went back to the question marks when I rebooted. I pulled all three cards and tried again. It would boot occasionally, but mostly just the question marks. I powered it off and waited about 30 seconds before powering it on again and… when I powered it back on some of the magic smoke came out of the back of the computer. I quickly killed the power to it. I didn’t see where the smoke came from because it was behind the computer and I was in front. So I performed the standard technician’s test for such an event and carefully smelled each component. As I was holding the computer in my hands, I turned it over and to smell the back of the power supply and I heard something rattle! Oh no! Did I burn up a chip on the main board and the silicon burst? In my days working at the local ISP, I had seen that happen before with dial-up modems when lightening would strike the telephone lines and there was no surge protection in the phone line. I looked at every IC carefully and did not see any with visible damage. I decided to pull the power supply and try to find whatever was rattling. As soon as I had the power supply in my hands, I realized that the rattle was a component inside the power supply. I had another one that was a known good spare ready to go. I installed that one and was back in the saddle again in no time. But I still got the screen filled with question marks and no booting. I decided that it was time to pull, clean and check each RAM and ROM chip. I pulled the first RAM chip and found a promising lead into the random, but mostly bad behavior of the machine – corrosion on the IC pins.
I took out my electronics cleaning kit, which consists of a bottle of 91% isopropyl alcohol and an old toothbrush and began cleaning the pins on all RAM and ROM ICs. That Black Goo of Death was really on there! The alcohol would barely touch it. I decided to take more drastic measures and I grabbed a #000 machinists slot screw driver and carefully scraped each pin, one at a time, until they were all clean. After cleaning each chip, I cleaned the sockets with the alcohol and then reseated the chip, making sure each pin was lined up and making good contact.
I repeated this for every RAM chip and moved onto the ROM chips and CPU. Once they were all cleaned and reinstalled, it was time to fire it up and give it a try. It booted and finally showed me the “APPLE ][” message that I was hoping to see. I power cycled it several times and it was stable! My victory high was short lived because I noticed that the video outfeed was offset to the left by about 2 inches. The monitor that I am using is an A2M2010. It has that classic Apple II green phosphorus look that I just love to see. This particular one spent the majority of its life in one of the local elementary school system and it has the school’s name scratched into the side of it.
Now, this particular monitor does not have any horizontal adjustments that can be accessed without removing the back cover and exposing the high-voltage components inside. I usually try to avoid this particular area of an CRT monitor, as I have heard many stories (one particularly nasty incident that happened in my cousin’s college electronics class) about the dangers of electrocution and high-voltage burns that can happen even with the power cable unplugged. I searched the Interwebs for any reference to this problem and how to solve it. I found this article from comp.sys.apple2 and it really seemed to match the issue I was having. The article did not seem to have any conclusive answer for how to solve the issue, so I posted a new thread to the group, linked that post and asked for some advice. I was advised to try another screen. I tried my other A2M2010 and it was the same results. Then I tried a modern 720p LCD TV with a component input and that was centered, although it looked like garbage. The colors looked like they were inverted. I decoded I would need to open the A2M2010 monitor up and see what I could find.
[DISCLAIMER: OPENING A CRT MONITOR AND EXPOSING THE COMPONENTS WITHIN CAN KILL YOU. KNOW WHAT YOU ARE DOING AND UNDERSTAND THE RISK BEFORE YOU DO IT.]
I removed the rear case from the monitor and found the H-SYNC dial on the circuit board and quickly found that if I rotated it very slightly, it would move the picture closer to center, but as soon as I rebooted the computer, it would be out of sync and the screen would be flipping very rapidly in a horizontal direction. This would not work. My last effort was to rotate the two centering rings on the back of the CRT tube itself. (I was wrongly referring to these as ‘convergence rings’ until Andrew Wells corrected me – Thanks Andrew)
It may be hard to see in the picture, but there are two brown colored rings here and when you rotate one of them, you move the picture vertically and when you rotate the other, you move it horizontally. A few adjustments between the two and I was in business. My video was now perfectly centered.
With my video issue fixed, it was on to the cards that were in the machine. I started with the Disk ][ card. It worked without any more than an alcohol bath. I needed something to run on it that was 48k ][+ compatible. Michael Packard has just released a beta of his new game called OidZone and I knew that it would run on 48k of ram. I used ADTPro on my IIe to make a disk from the image and loaded it up.
The game worked great and the machine was able to play it without any issues.
Next, I used the same IIe/ADTPro combo to make a disk for the Apple II+ techincians diagnostic disk. I ran this disk and it had a ram and rom tester. All my onboard ram passed the test and so did the roms.
After this, I decided to test the 16k language card. It was a Jameco JE868. I could not find a manual on it, but I did pull/clean/reinstall all of the ICs and RAM chips on it too. While cleaning it, I noticed that each bank of RAM has a 104 capacitor installed, probably for cleaning up any noise on the circuit. The cap on the very first bank on the left had it’s right leg burned completely off! Luckily, I had a replacement cap of the correct specs on hand. I replaced that cap, inspected the results, and it looked pretty good. I installed the card into slot 0 on the machine, inserted the Apple II+ diagnostics disk and ran the RAM and ROM test and it passed all tests!
Since then, I have not had much time to use it, but the times I have used it, it has been rock solid. No more failures to boot, no more lock ups/freezes, and certainly no more exhaling puffs of magic smoke!