Recent content by DJ68K

I second what psa425 says: It's definitely a broken trace somewhere in the video RAM circuit. I fixed it on my SE/30 by toning out every single leg on those chips looking for broken continuity. As you said, there's 1 bad and 7 working pixels. It's an 8-bit data path (4 bits per VRAM chip) and...

Are you currently having a problem with the board? Your original post doesn't say you're having any problems. Other than cleaning residue all over the board the board looks okay. Are you just asking for reassurance before you plug it in and try it for the first time? If so, use your multimeter...

Is C2 hooked up at the top of the picture? Looks a bit shifted towards the rear of the board. Otherwise, what's the exact hex code underneath the Sad Mac? Knowing that can help troubleshoot where to look on the board.

GENTLY pull out any socketed chips including the CPU and document where each one went (and in what direction!), spray the board down with your favorite motherboard cleaner and let it soak for a while, rinse it under running water in the laundry sink, do that a few times until you're confident...

I threw a quick Youtube video up here: On page 2 of the Apple SE/30 schematics, when I probed for C32G (between crystal Y2 and chip UH7), I only got a constant tone. When I probed C32M coming out of UH7, it was much the same. Only from pin 18 (C16M) on the Glue Chip do I get anything that can...

Disclaimer: I can read schematics but I’m not skilled in theory of operation. Therefore I spend way too much time toning out traces and not enough time reading data sheets and knowing how chips do what they do. I learn how things operate as I go. It’s decently entertaining, but not necessarily...

I remember dealing with these passwords back when I worked at an Apple Specialist; it's a password that locks the hard drive so someone else can't use the computer. In fact, it's a feature of the hard drive itself, and I'm surprised how little information there is about it on the web. I might...