So, five Mac IIci walk into a shop...

The Macintosh IIci is a special computer for many Apple fans. It was a powerhouse in its day, and some of us have happy memories of exploring System 7 on these lovely boxy computers. A few may have seen my recent Twitter posts talking about my efforts to restore five Macintosh IIci. I acquired them in two batches. A few years ago, I won an eBay auction for two Mac IIci. And a few months ago, I added three more when Facebook Marketplace took me to a nearby town to pick up the Mac IIci and a few Mac IIsi. The seller got them from a school and left the computers in an outbuilding for many years.

I waited to restore the two eBay systems until I felt reasonably comfortable in my skills to nurse them back to health but then I got distracted by other projects. Now, after a several-month-long hobby hiatus, I decided it was time. (Actually, #Marchintosh would have been a better time, but so it goes.)

While I'll eventually write a post on my project blog, I decided to try documenting my work on TinkerDifferent so others can check my work and offer suggestions. If this is not your bag, it won't bother me if you merrily skip over this thread.

For the sake of clarity, I'll break down the systems below:

• Alpha - Looked to be in good shape aside from leaky capacitors and resulting crusty ICs and vias. This system was manufactured in 1989 and is a bit different from the others with a slightly different logic board number (820F0242-02 versus the other's 820-0242-A), black-colored NuBus connectors, white plastic SIMM sockets, EPROMs, and a ten-digit serial number instead of eleven. (Acquired from eBay.)
• Bravo - Capacitor leakage was more severe, and two small ICs (UD13 & UE13) were missing (one found rattling around the case). It was manufactured in 1992. (Acquired from eBay.)
• Charlie - It looked to be in good shape but with the usual capacitor leakage. It was manufactured in 1992. (Acquired locally.)
• Delta - Usual capacitor issues, but not as crusty as others. Unfortunately, this unit was battery bombed. It was manufactured in 1992. (Acquired locally.)
• Echo - A rodent's den. Considerable debris, droppings, and stains on the logic board. Frighteningly, two brown recluse spiders were hiding under the logic board. A real mess. (Acquired locally.)

As for cards, there were two PDS cache cards, one Radius NuBus video card, and three NuBus Ethernet cards.

I stripped all the computers down to determine what I was dealing with. I then removed all the caps on the logic boards, ordered replacements from Mouser, and placed each in an ultrasonic cleaner. I then manually cleaned and visually inspected each power supply. I also checked for a steady 5V of continuous power. Three of the PSUs were Astec AA15831 (from Charlie, Delta, and Echo) while one was an Astec AA15830 (from Alpha), and the other was a Delta Electronics SMP-120EB (from Bravo).

Once the units dried, I started with Charlie, as I expected the least amount of trouble.

When I removed the caps from Charlie, I disappointedly lifted two pads and partially lifted another--all near the sound chips (telling me the leakage was worse than I thought). So I ran bodges to C2 and C3. After that, the cap replacements went pretty well, except that I ordered tantalum 16V 10uf capacitors to replace the small electrolytics, and the tantalums barely fit over the small pads. I then discovered that some time ago I'd ordered capacitor replacement kits from Console 5 for the first two Mac IIci acquired from eBay, so I stole the small caps from the kit for Charlie.

When I powered it on, I was greeted with Chimes of Death. Then it hit me that I forgot the IIci didn't have onboard RAM, so I popped in four SIMMs and tried again. This time I got a solid bong but no video. I also discovered I couldn't power it down with the rear power switch. So, I pulled out the board and realized I'd done a poor job cleaning the ICs and vias around the soft power circuitry. I also worked on the legs of the IC and vias below NuBus slot C. With the next test, soft power worked perfectly, but still no video.

I was using an Apple Color Plus 14-inch Display to test the video, but since this is a low-end Goldstar CRT, I pulled out an Apple High-Resolution Display I haven't restored yet. However, when it powered on, there was still a black screen. Finally, I started thinking about RAM. I knew the IIci lacked dedicated VRAM, so if the SIMMs were faulty, it might result in no picture. That's when I caught my foolish mistake! When I popped in the 30-pin SIMMs, I put them in the lowest numbered slots according to the silkscreen, but I missed that above the slots it clearly showed that Bank A was on the right, with Bank B on the left--the opposite of what I thought. When I installed RAM in the proper Bank A, I was greeted with a flashing disk question mark!

That's as far as I've gotten so far. Since I'm a weekend hobby warrior, updates will be spotty, but I'll keep you posted on my progress.

 

[RetroViator]

I have made modest progress since my last post. First, I assembled an external BlueSCSI, though I'm having trouble with it. I'm getting five red blinks, so it's not seeing the SD card. I've verified the card and image work in my internal BlueSCSI, and I've checked the solder connections and verified connectivity between the SD slot and the Blue Pill. I set the problem aside for now, but I'll get back to it. Besides, since you can't have too many BlueSCSIs, I ordered an assembled unit from Tom Barber, which should arrive soon.

In the meantime, I put together a helpful System 7.0.1 image for the Mac IIci. Early System 7 feels right on a hearty 68030 machine. I enjoy the simple elegance of primary colors and stripped-down control panels and system extensions.

I lost track of time as I whittled away at Alpha's board. This is the oldest system, manufactured in 1989. The logic board is slightly different from the others manufactured in 1992. I'm learning that any dull gray solder is a problem waiting to happen. I hit suspect IC legs and vias with flux and heat them until I see the nastiness begin to boil away. I then wipe the area clean with isopropyl and hit it again with flux and heat and some mechanical scraping with a dental pick until I can get fresh solder to stick. Given the electrolytic leakage on all the boards, I'll be doing this for quite some time! While some of the suspicious areas may be good enough to work, I'm working them over anyway before I install the new capacitors. I'm fairly optimistic this Alpha IIci will be up and running soon.

 

[Volvo242GT]

If the nubus slots are dead on any of the boards you're working on, follow @pfuentes69's advice and replace the 74ALS240 chip below C16 with a new one.

Here's his thread: https://tinkerdifferent.com/threads/problem-with-iici-and-nubus-cards-solved.317/

-J

 

[RetroViator]

If the nubus slots are dead on any of the boards you're working on, follow @pfuentes69's advice and replace the 74ALS240 chip below C16 with a new one.

Here's his thread: https://tinkerdifferent.com/threads/problem-with-iici-and-nubus-cards-solved.317/

-J

Good to know. Thank you.

 

[Volvo242GT]

Not a problem.

 

[RetroViator]

I'm taking my time working on Alpha's board--learning as I go. I could talk myself into thinking the board would fire up as is, but I'm enjoying honing my repair process. It's funny how this hobby adds difficulty as you level up. It starts with SMD cap removal and replacement, then running bodges, then IC pad and leg clean up, then cleaning vias, then..., etc.

Upon close examination, Alpha's power circuit area was quite grimy. The sound circuits and one cap near the NuBus slots show leakage, but not to the degree of the power circuits. Many vias are dull and gunky, and all the nearby IC legs are gray and fuzzy. After some spot work here and there, I decided to use hot air and remove the worst-looking ICs, and I'm glad I did. While I tediously cleaned each leg before I decided to pull the chips, I now realize I was getting the front of the pad, leaving the back half--the portion that should make contact with the chip--in terrible condition. Also, once removed, I could clean the legs properly, especially the backside of the legs, which would otherwise go unnoticed. All those helpful tips from @Branchus, @Mac84, and others are making sense!

So I'm going slow as I balance work, family, and hobby, then endeavor to understand the repairs and do them the right way.

 

[RetroViator]

I've had a long break from my Mac IIci because I acquired a horde of Commodore goodies. While I don't have as strong a personal nostalgia for Commodores, I couldn't pass up this collection. It has taken me quite a while to sort through it, clean things enough to not feel dirty handling them, and then store them on shelves so I can get my garage floor back.

Now back to my flock of IIci, I did my best to get Alpha in great shape, but upon testing, it's dead as a doornail. Though I've spent hours looking at it through my microscope, more inspection and probing is needed. So, I decided to leave Alpha in its non-working state for now and slide over to Bravo. Bravo was the second of the two units I acquired from eBay some time ago. I knew this one would be tricky because two LS logic chips (UD13 and UE13) around the power circuitry had fallen off the board due to corrosion. Aside from the missing ICs and evident leakage, it looked okay.

The first order of business was to order replacements for the 74LSHC132 chips that had rotted away. I ordered a pair of MC74HC132ADG from Mouser, hoping they were the appropriate replacement. Turning my attention to the board itself, I was pleased to see all the pads were intact, and though I had washed this board in the ultrasonic cleaner, I could still see the lines where the electrolytic fluid had soaked into the board. With my trusty scalpel (a tool I didn't have when I worked on Alpha and Charlie), I scraped away the solder mask from discolored traces and applied IPA, then flux, then flesh solder to stop the corrosion from eating away the traces. Once missing ICs' pads were clean and holding flesh solder, I set about attaching the replacement logic chips to the board. My Microscope was a big help as I tried to hit each leg with solder, but not too much to make a mess of things. After both chips were attached, I checked the continuity between each leg and the pad, then followed the traces to ensure the chips were electrically connected to the right places. That's when I noticed pins three and four of UE13 did not trace through the via to the back of the board. Frustrated, I pulled out the hot air, removed UE13, and looked around. Like many vias in this area, it looked rough and required considerable cleaning with flux and heat. While I had removed much of the old corroded solder, it seems the via was too damaged to carry the signal. I assumed I'd run a bodge through the hole to wherever it was attached on the underside of the board, but that's when I discovered it didn't run anywhere on the other side.

I was concerned the via connected to something inside the board, and I grew despondent. I looked at the Bomac schematics, but I was not familiar with how logic gates are drawn, so I was confused. Luckily, someone on Twitter checked the schematics and said it looks like pins three and four only connected to each other and did not tie to anything else. This helped me understand the drawings, and I pulled out a resource on LS chips and the datasheet for the 74LS132. I then learned that pin three is the output for the first logic gate on the chip, and pin four was one of the two inputs for the chip's second logic gate. For some reason, both pins' traces run to a via that ties them together and pops out the back of the board. I decided to stick a leftover component leg in the via hole and flow solder on both sides. I left a nice solder blob on the top of the board to bridge the traces for pins three and four, but I realized the IC sat right on top of the via, and it wouldn't sit flush with the solder blob. So, I cut some tiny enamel wire, stripped the wire with the scalpel, and connected the traces for pin three across the via to nowhere, then back down to pin four. In the end, it was not pretty, and I probably should have left the original solder blob in place, but everything was linked, even the mystery solder point on the back of the board, and the replacement LS chip would sit reasonably close to the board.

After testing all the connections, I reattached UE13 and finally started installing the replacement capacitors. After getting the SMD and through hole capacitors in place, I carefully went over the board, looking for more suspicious traces. I found a few more that I scraped, cleaned, and covered with new solder mask. Then I was ready to install some RAM and give it a test.

The first time I hit the switch, I heard a happy bing and saw a grey screen--no flashing disk icon. I powered it off and back on. This time I heard the bing but then heard the chimes of death and no video. So I assumed the RAM was bad. I found another set and powered it on again. This time it binged, with no chimes but a black screen. Thinking the video might not work if the second set of RAM was also bad (but in a different way), I tried a third set. This time I was back to chimes of death and a black screen. So, I found a fourth set of SIMMs, and I was back where I started--bing, no chimes, and a grey screen. I had to leave it there for now as real life invaded my time, but I'm optimistic that Bravo will work once I iron out a few wrinkles.

I recently acquired a Retro Chip Tester with the 30 and 72-pin test connector so I can check my old RAM. However, the Retro Chip Tester is a challenge to assemble, so my SIMM testing will have to wait until I get the tester's board populated and ready for business.

Having worked on three of the five IIci, one is in great shape, one is mysteriously dead, and one is half alive. More to come.

 

[trag]

Great work on the IIcis, but more importantly, I'm jealous of your workshop. Looks wonderful.

 

[retr01]

Hey @RetroViator! Wow, nice! Are those round stickers (orange, green, and pink) triaging the parts based on condition? Or color coded for A through E?

 

[RetroViator]

Hey @RetroViator! Wow, nice! Are those round stickers (orange, green, and pink) triaging the parts based on condition? Or color coded for A through E?

Correct on the second count. The round stickers are used to identify which parts came from which systems.