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On my other CC, with the mystic board I was getting issues when the voltage dropped to around 4.6V, I think. However, the issue looked completely different - the computer would still power on, but I was getting a death chime. This one won't even power on with the mystic board in place.

I've been reading a bit how optoisolator works, and it does seem that a decaying dLED inside of it could cause a voltage regulation issues, and specifically lower voltage issue. Not much point posting a photo of it now as I"ve mostly scraped the green corrosion from the IC's legs, but some of...

I've made a potentially significant discovery on the nature of the problem. Once I removed the LC575 board, and placed the original CC logic board, the computer boots fine. It of course cannot display the VGA resolution correctly, so the image is distorted in terms of width and barrel...

Thank you, I will look through that thread carefully. I was thinking of replacing the optocoupler and those diodes, even though nothing looks obviously burned. I’m worried it’s the flyback though. I can hear a brief buzz from it while the LED is on, and it all shuts off a moment later. Maybe...

I spotted a "for repair" CC analog board on Ebay a few weeks ago. Seller said that the board was VGA modded and worked fine for a while. Seller then attempted to undo the VGA mod, but something got messed up in the process, and it stopped working. I got this board thinking I could try to repair...

Would it be possible to use a thermal tape with the large copper heatsink? I'm not so much interested in maximum performance, but would rather keep the machine as silent as possible (I've already installed a Noctua fan as per your other video's instructions!) I'd also try to install it in as...

Thanks for all that info! I wonder if my first order of business here should be to get a heatsink, because I've noticed that I can only achieve a stable overclock to 45MHz while the CPU is not too hot. Once it gets hotter, the computer freezes at 45, and I can only stably do 40MHz.

Yes, I can confirm that Tattletech is reporting the same for me: Mac LC 580 | Performa 58X (99) Here it is. These sticks are actually Apple branded, and dated 1991:

I too suspected the VGA mod is why @JDW didn't have this issue (like you, I also changed the System resource to make the machine boot correctly) - glad to see you confirmed it, and got it working! I guess the reason was the modification in the system resource files I did to make the LC575 board...

I watched @JDW video on this, and immediately rushed to try the "475 Overclock" Control Strip on my Color Classic Mystic. At first, it didn't work no matter what I tried. The latest 475 Overclock 1.0.4 didn't work on either System 7.6.1 or 8.1. Neither did the older 1.03 version of 475...

Sorry for the blurry photo, I was trying to show in which direction they need to be straightened. The two tabs I'm referring to are the ones that connect to two places I've circled in red here: I don't believe they make any ground/electrical contact with the board - which makes them that much...

Whew. Just recovered from what seemed like a total disaster, and it turned out the culprit was the analog board connector, and notably also those metal tabs holding the analog board to the ground shield not being perfectly straightened. Well probably - I need to test it some more. Short story...

Yes, that's the process I was referring to. I was mulling the idea that all that's done there can be put on a 3-pole double throw (3PDT) switch with some careful wiring, so with one flick of a switch (while the computer is powered off) you could go between the original resolution and the VGA...

Would you mind sharing some photos of how you've done this? I've been thinking about that exact thing, as the entire process appears to be disconnecting things from one another - so it appears it could be done in such a way that one switch could control the mod on and off. Maybe this could be a...

I was wondering about that, but I don't know if any of that is repairable or adjustable. I see that the CRT has those plastic strips that can be moved around - aren't they in control of some magnet positions? In any case, on mine they seem to be factory glued, so I don't think anyone ever...

I see :( I guess I will just have to accept it, and feel lucky that I have another one that doesn't have this issue.

Yes, it's a fax software extension. It's on the system that's on the HDD that was in the computer when I got it. The extension even makes some noise that's probably supposed to sound like the paper being spooled out of the fax machine. But it's really more like static noise, and at first it made...

Thanks! I don't think there is anything magnetic in the environment, as I have another Color Classic which I've been repairing - that one has other problems, but the screen looks perfectly uniform when the computer sits in the exact same spot where I'm testing the CC with non-uniform screen...

I purchased a non-working Color Classic with an intent to repair it, and after fixing up some fairly extensive logic board damage due to capacitor leakage, and of course doing the logic board recap, the computer was back up and running! Two problems remained however: there was some picture...

I've had similar flickering on the Color Classic, although it involved color changes and instability. Much like yours, it was most pronounced during the warmup period of 10-15 minutes. Problem went away after I recapped the analog board (I did a full recap) and also touched up any suspicious...