Mac IIci Success Story

[rikerjoe]

Hey all - I recently acquired a Mac IIci. Although it is not the IIfx on my Holy Grail list, it is a close second. While I was running skiprope simulations on my IIfx in the early 90s, many of my NASA colleagues were doing work on the IIci.

As you can see, it was a little rough looking. Very yellowed and scuffed case, and the dust bunnies inside were amazing.

i did a complete disassembly, cleaning, restoration of the floppy drive, and retrobrite of the case.

I took a careful look at the logic board and saw the telltale signs of capacitor leakage, which we all expect of a board of this vintage. I removed the old caps (only had one popper) and took a careful look at the neighboring traces. Sure enough, UE13 had a broken trace on pin 1. I decided to remove and clean the chip and pads and do the trace repair. I also noted a broken trace in the sound area from C5. After effecting that repair and installing the replacement tantalum capacitors, the board was looking much better.

I put the board into its freshly retrobrited case, plugged in an ADB keyboard/mouse and multisync monitor, and…

Success! Chimed the first time.

I’m looking forward to playing around with the IIci, as I’m sure many of you that have one do. I’ll be on the lookout for a cache card, and perhaps a monitor and Ethernet card.

 

[Eric's Edge]

Very nice! I recently acquired a IIci almost as yellowed. I'll retr0brite it someday.

 

[Volvo242GT]

Looking good. I would verify that the Nubus slots are working. UH1 is looking a little grimy, like how mine was. Luckily, the chips are still available and fairly cheap.

 

[rikerjoe]

Looking good. I would verify that the Nubus slots are working. UH1 is looking a little grimy, like how mine was. Luckily, the chips are still available and fairly cheap.

Yeah, C16 definitely barfed its goo and made UH1 grungy. I scrubbed it but didn’t remove it for my initial test. I’ll take a closer look at it and definitely will test the NuBus slots once I acquire a card. Thanks!

 

[retr01]

Good job, @rikerjoe!

*GASP* You worked for NASA?! Do tell me more! What did you do at NASA?

 

[-SE40-]

As new!
Great job!

I may have a cache card for you…
Can you give me a serial number to verify?

 

[rikerjoe]

A follow-up to the Mac IIci success story....

Playing around with the IIci, I found that if I ran it for a few hours, it would shut off and attempt to restart, fail, restart, etc. until I pulled the power plug. If I left it unplugged it for a few hours, it would boot normally, then repeat the power failure as before. Naturally, I thought "power supply", which I have not recapped yet. As a test, I pulled the power supply from my Centris 650 and stuck it into the IIci. I got the same behavior, which likely ruled out the IIci's power supply as the problem. I therefore targeted the IIci startup circuit, thinking that perhaps I missed a broken trace or had a chip problem. I targeted the 74HC132 chips at UD13 and UE13, and while poking around one of the legs fell off the UE13 chip. I ordered a replacement 74HC132 from Mouser to replace the UE13 chip and proceeded to remove both of the 74HC132 chips, clean UD13, and do some continuity tests. For good measure, I also removed and cleaned the 74HC74 chip at UB13. Sure enough, I found several broken traces around the pad for UD13 pin 6, which is supposed to connect to pin 2 and pin 10. After a few bodge wires, cleaning and replacing the original chips at UB13 and UD13, and installing the replacement MC74HC132ADR2G from Mouser at UE13, I powered up the IIci and happily observed no more power outages - I ran the IIci overnight with Snooper and it was still humming away just fine this morning. The IIci now also powers off correctly, which it didn't do before (previously, it would show the same "It is now safe to power off your Mac" like with an SE/30 when selecting Shutdown from the Finder).

Now that the IIci power problems appear to be resolved, time for the next challenge. @-SE40- was kind enough to send me a IIci cache card that I am currently troubleshooting. I replaced the two electrolytic capacitors with tantalums and tried the cache card in the IIci. I get a boot chime but the CRT does not light up, telling me that something is failing during POST. I'm going to guess there is a broken trace somewhere on the card, or a problem with one or more of the SRAM chips on the card. I'm curious if anyone out there in the Tinker Different universe has done troubleshooting of one of these cache cards. If you have, I certainly welcome any words of experience. Meanwhile, I'll keep troubleshooting and perhaps will have some good news to share down the road.

 

[-SE40-]

Hey Joe,

Glad the card arrived well on the snailmail.
Hope you get these issues sorted soon.

Have a great weekend!
Greetings Chris.

 

[ClassicHasClass]

By far the part that failed the most in my very long running (as in decades) Mac IIci running NetBSD was the cache card. It would chew through one every couple of years and crash, recapped or not. I now run it without one.

 

[-SE40-]

@ClassicHasClass , whats the cause,
whats eaten away?
Does the Sram get to hot?
Can these simply be replaced?

 

[ClassicHasClass]

Not sure why. This occurred even with a recapped card. But this IIci is running 24/7, so it's possible they have a finite lifetime most collectors will never run into. Meanwhile, it's far more reliable, even though it's noticeably slower, just to run it without cache.

 

[rikerjoe]

I managed to score one of these beauties for my Mac IIci, an Interware Booster 40-33 sporting the version 1.1.1 ROM from 1994.

It may be a little hard to see above the heatsink, but it is rocking an XC68040RC33M variant of the 68040. Below is a MacBench 3.0 comparison of a stock Mac Iici, with a cache card, and with the Interware Booster. Results seem on par with expectations I've seen elsewhere.

 

[-SE40-]

Thats a great addition Joe!
Never heard/read about this card.
So it replaces the cache and fpu.
Also the original processor is bypassed by this then, fully running the 68040

Just out of curiousity, how does performance compare to a later 68040 quadra system?

 

[rikerjoe]

Here are the same benchmarks as before, with the addition of a Centris 650 (68040 @25 MHz), Quadra 630 (68040 @33 MHz), and a Color Classic Mystic (LC 575 board) overclocked to 40 MHz. Interesting. My takeaway is that the Interware Booster is OK for boosting performance some, but doesn't come anywhere near matching a true 68040 machine.

I've really grown to love the Mystic, and plan on pushing it closer to 50 MHz after I replace the caps with OS-CONs and test the VRAM.

 

[-SE40-]

Thats a great comparison!
You where able to repair the IIci Cache card?
The interware did help extending the lifespan on the IIci. Great!

The Mystic is indeed fastest here.
I feel compared to the tuned Mystic the standard Q630 is a good second choice.
What would happen if that one is pushed to its limit

 

[rikerjoe]

I managed to get a second cache card. I’m still curious about troubleshooting the card you sent, especially with the anecdotal evidence of cache cards commonly failing as mentioned earlier in the thread. I’d like to know why.

 

[-SE40-]

Yes, the failing of the ci cache card is a strange story.
But obviously its corrupt somehow.
Pity it did not work…

I believe the 575 was never that popular around here….but may be able to get a 475 for Christmas
You know if that board would make a good tuning candidate?

 

[rikerjoe]

I don’t know much about the 475, but @Kay K.M.Mods created the Spicy O’Clock and he lists the 475 as an overclocking candidate.

 

[retr01]

@rikerjoe is correct. @Kay K.M.Mods' Spicy Clock from this shop is the real deal for the 475. The catch is that fast VRAM and OS-CON 47µF and 100 µF caps are needed for higher clock speeds, such as 50 MHz. I recommend SMC VRAM to complement the Spicy Clock.

 

[-SE40-]

Ok, in that case its worth a visit to the attic of an old friend of mine…..
Dont know the 475 condition, so it could be battery bombed by now.
Fingers crossed.