Apple II Plus - Trash to Treasure - Part 1

One of my goals in Retro Computing is to learn about older and older computers, and work my way back in time, one generation of computers at a time.  The nostalgia factor is certainly important for me, but I’m also interested in the tech that came before.  In my own retro computing development, I’d been keeping my eye out for an Apple II Plus machine.  I have an Apple IIe that I’ve already mentioned, and have been interested in the experience of using the original Apple II's since I’ve never owned one of the original “Trinity” of home computers.  Finding an original Apple II (not a Plus) seems a bit out of my price range at this point, but perhaps someday I’ll be able to repair an original Apple II.

My opportunity for a II+ came in mid November of this year, when a trusted retro computer seller on Craigslist posted a Bell and Howell “Darth Vader” computer in need of some serious help.  As Apple fans will know, this was a partly re-branded Apple II Plus, Bell and Howell painted it black, and since it’s a bit more rare it’s more valuable.  The seller and I had a phone conversation about the state of the machine, which was poor, but I was able to convince him to sell me the machine regardless of the state.

The state of the computer was not good.  The biggest problem with this computer was that the top cover had been removed before the computer was stored.  This meant that dust and dirt got inside.  I even found a couple of acorn tops as I was cleaning inside.  The main board had a significant amount of dirt on it, and there was one chip (one of the ROMs) that had bent pins  It seems likely that something very heavy was dropped onto this chip causing the pin legs to bend.

So on intake, it was obvious that I should not even try to power the machine on without doing a lot of cleaning first.  I started by taking the top half off the case, removing the power supply, main logic board, keyboard, and backpack from the unit.

I started with the logic board.  I used the cleaning method that Adrian Black has been demonstrating, warm soapy water in my basement laundry sink.  I used Dawn dish detergent, warm water, and brushes for the initial cleaning.  It took quite a bit of time because there are more than 80 chips on the board that all needed to be cleaned around, but it was very gratifying to see how much better the board looked after.

Also, at this point I was able to get a look at the date code on the board and discover that this II Plus was made in 1981, so this would have been the third year of production for the II+, starting in 1979.  After the initial clean of the logic board, I shifted gears to the power supply.   I had already serviced the power supply in my Apple IIe, but this one had an additional rivet on either side that I had to drill out.  The RIFA cap was certainly on its way out (bulging) so I'm glad I saved the smelly mess associated with a power on test.  I removed and replaced with a new X type filter cap that I had in stock.  When I put the power supply back together and tested voltages, it was not working correctly.  I remembered that as I was re-assembling it, the circuit board had flexed quite a bit.  Since this board has a heavy transformer in the middle, I think this design is prone to getting cracked solder joints at the transformer.  After I reflowed the joints on the transformer and several other components while I was at it, the power supply was working with all voltages reading good.

Next, I tackled the keyboard.  One of the things I dislike about the Apple II Plus is the use of ribbon cables with DIP connectors on the end.  I didn’t realize how fragile these were, and as I was taking the computer apart, I broke pins on the interconnect cable between the logic board and the keyboard.  Thankfully, I was able to find this article online, I ordered the replacement cable from DigiKey, and it is on the way.  This keyboard has the SKCC Short Stems with the extenders installed, and it ended up being significantly less dirty than the previous one I’d cleaned. My son especially enjoys keyboard cleanup (I think it reminds him of Legos), so he helped me with this part of the project.  We pulled all the keys and gave them a soak, he helped me go over them all with a toothbrush, they look great.  I then worked on the keyboard deck, using the same procedure I described in the Apple IIe article with lots of Isopropyl and DeOxit.

The next day, after the main logic board had dried, and on further inspection, I needed to do more spot cleaning on the logic board.   This time I used Isopropyl and  Q-Tips to get in close to each chip.  I was also able to pull out the damaged ROM chip, inspect the socket, and re-bend the pins back into place.  I made a note of the location since this may require further inspection and repair, but at first glance, it looked like that socket had not been damaged, and none of the pins broke off.

At this point, I was able to give the system its first power up, a very exciting moment indeed.  Sadly, there was no video from the machine.  So, this sent me back to looking more closely at the board.  What I noticed was that because there had been so much dirt on the board, there was dirt on the legs of many ICs where they entered into the sockets on the board.  So, as time consuming as this would be, I felt it would be important to pull every IC out of the socket, inspect the IC, clean the legs if needed, and spray De-Oxit into every socket.  Given that there are more than 80 ICs, I divided this task up into a couple of parts.

During this part of the repair, I broke multiple legs off three different ICs.  Again, using another trick I’ve seen from Adrian Black, I was able to solder a small (28ga) solid copper wire back on in place of these legs and get the chips plugged back into their sockets.  I’m super happy that I didn’t have to order any additional chips. (Yet, knock on wood)

On completion of reseating all of the chips on the board, it was time for another power on test.  This time, there was Video, along with the Apple ][  logo at the top and the ] BASIC prompt, a very happy moment indeed!

At this point in the repair there remains a good deal more work to do; the keyboard is non functional, the RAM should be tested, I should add a Floppy Disk controller, but this article has gotten a bit long so I will leave off here for now.

Apple IIe Repair and Use

The Apple IIe was the first computer I spent a significant amount of time working on, because it’s the computer they had at my junior high and high school in rural Wisconsin.  I remember playing Oregon Trail and the original Castle Wolfenstein at school in the school library.  But these were also our workhorse computers that we used to learn BASIC programming and for word processing with AppleWorks.

So, it was with great excitement that I started in watching Adrian Black and various other vintage and retro tech YouTubers dig in on these Apple II computers, learning how they work, how to repair them, and work on cleaning and restoration.  Full schematics are avaliable, and really excellent troubleshooting material from back in the day is also up on the ‘Net.

Because I’m always trying to keep my hobby affordable, I didn’t rush out and buy the first Apple II computer I could find, I made several offers, and was finally able to land a nice-looking example from a family that was cleaning out their basement.  The lot of items for sale included the Apple IIe itself, an Apple Color Monitor, a single Floppy Disk drive, and many floppies and manuals.  I purchased this at the beginning of October, the seller “didn’t know if it works”, so I was prepared for the fact that it probably wouldn’t work.

So after getting the unit home, the first thing I did was to take the power supply out.  The RIFA cap had blow, I could still smell it. I wondered if they had tried to test it and let the smoke out of the cap recently.  I removed the RIFA cap and then tested the Power Supply voltages.  Those checked out good, so I tried to power up the monitor next.  The monitor powered up without incident.  Then, the moment of truth, I powered up the computer (without any cards in it), and it booted right to the BASIC prompt.  A very exciting moment!

After poking around for a few minutes, I realized that some of the keys on the keyboard were not working.  The keyboard was filthy.  It seems likely that this machine had been stored in the previous owners basement, perhaps for decades.  The next order of buisness was to clean the keyboard throughly.  I washed the keycaps, and did what I could to clean the keyboard from the top and bottom with liberal use of Isopropyl Alcohol.  I sprayed a liberal amount of DeOxit into each key and cycled each key a dozen times or more.  This brought back about 1/2 of the non-functioning keys, but there were still three keys that I had to remove.  I was able to take these three key switches (SKCC long stems) apart and clean the removable metal contacts, then replace them in the switch housing.  Try that with a computer that isn’t 30 years old!  This restored all the keys on the keyboard to full function, and it’s been working fine ever since.

The next set of repairs centered around the Floppy Disk drive.  I was excited about getting the Apple Disk II device up and running, there’s something so nostalgic for me about the sound that the Apple II drives make when the computer starts.  When I first received the drive, I heard something rattling around loose inside and so before powering the drive up, I needed to open the drive and determine what that rattling sound was all about.  It turns out that the lever on the bottom left floppy disk guide had broken off.  This lever must remain connected, yet flexible, so I used some strong Gaffers tape to get it back in place so that when a floppy was pushed in, that lever would sense the write protect notch and operate the micro switch inside the drive.  I don’t expect this repair to last forever, but it’s been OK so far.

After this, the Floppy Disk drive did work for some time. After going through about the first 20 disks in the collection, it stopped working, and I plugged in FloppyEmu and was back up and running.  Honestly FloppyEmu is such a great product that I’ll probably keep using it, if it wasn’t for that distinct sound, and wanting to check out the programs on these disks that came  with the computer.  So, eventually I opened the drive back up, an found this on the main drive circuit...

Look at the capacitor on the upper right hand corner.  The right end of the capacitor has completely blown out of the device and there’s literally nothing left inside.  I was able to replace all three electrolytic capacitors with caps that I had in my stock bins, and get the drive back up and running.  I hear that not much else can go wrong with these drives, so I expect this drive to be operating when when the last of the Double Density floppy disks wear out.

So, with the Apple Disk II drive as Drive 1 and the FloppyEmu as Drive 2, I was able to boot off of a disk copy program and copy various disk images back out to Floppy disk.  I was able to make ProDos disks this way, and some games like Flapple Bird.

Along the way I made some simple, silly mistakes, too, like accidentally pushing the color / monochrome button on the front of the monitor, then closing the door and forgetting that setting.  I spent almost an hour trying to figure out why the image was monochrome, then remembered the monitor setting, which I now understand is there to help reduce color fringing with text in 80 column mode.

Anyway, the Apple IIe is up and running and I just couldn’t be any happier with the result, what a classic machine!  It’s been my go to game machine for classics like Donkey Kong and Choplifter since it’s been running.  I’ve also been able to use it in testing a much more broken Apple II Plus machine, but more on that in a future article.

Do you have memories of Apple IIe?  If so let me know in the comments below, or send me an email.

Current State of the Lab Workbench

I thought I'd give a bit of an update about the current state of Steve's Digital Basement, as there have been quite a few upgrades over the last year.  Many of them inspired by Adrian's Digital Basement along with many other retro and vintage tech YouTubers out there.  I really appreciate their willingness to share the wins and the losses.  I share the belief that the more comfortable we can get with learning from failure and not being afraid to try stuff that we aren't good at, the more skilled we will become.  The perfect is truly the enemy of the good.

Since spending more time learning online about the surprisingly high quality of some of the Chinese devices out there, and since I've always wanted a Digital Storage Oscilloscope, I spent some time learning about the various low-cost brands out there.  I often shop the "Open Box" section of the online catalog at my local Microcenter.   They had this Silgent SDS 1052DL+ that sat in the store for quite a while, after the price dropped a second time, I picked it up.  I paid less for it than what I got by selling my old Tektronix analog scope.  I know that the Tek scope is likely to outlast this one, but in the meantime, I've got a really capable scope and I couldn't be any happier with this major upgrade at the bench.

I've also added a new Power Supply recently, it's a generic supply also from China, but has more current capacity than the BK Precision Model 1601.  I'll keep both for situations where I need dual voltages.

The other add from China is a component tester, it’s capable of doing ESR checks on capacitors, and that’s been very useful as I troubleshoot old devices.

The Hakko soldering station was one of my first upgrades when I started to get back into Electronics and repair, it has been a truly amazing tool.  I upgraded from a non-temperature controlled soldering pencil about 5 years back.  I no longer dread soldering, it's an absolute pleasure to use, and the results are significantly better.

In the upper left hand corner, you can see storage bins, I have a couple of sets of these with common electronic components.  I'm not stocked yet to do recaps and other repairs without ordering parts, but I do have some common components on hand, and I've been able to do some spur of the moment repairs without ordering parts, like recapping the control board on an Apple Disk II or recapping the Apple IIe card in my Mac LC.

Not shown in the picture, I have a tool box off to the side filled with hand tools.  This tool box holds; hand tools,  a Multimeter, and various magnifiers.

On the wish list, I'd love to get a really nice stereo microscope.  I previously had a powered Solder removal tool on my list, but I recently got the manual Soldapullt and this has been such a great hand tool that I'm not sure now that I need a powered desoldering gun.  If I start frequently removing ICs and connectors, I may change my mind about that.  I'd also like to get a hot air soldering gun, this would help with desoldering and resoldering Surface Mount components (at this point primarily to help with the ReCapping that I"m already doing).