Recent content by RetroViator

PSUpalooza This weekend I finally put together four additional Power-Up-IIusi replacement power supplies. This was pretty uneventful, as I figured out the nuisances with my earlier single PSU build. This time, I built each PSU up in an assembly line, simlar to my floppy restoration. I started...

You just reminded me that Golf, the horribly battery-bombed IIsi I got from a nice retired couple who were downsizing, came with a DayStar 601 Processor Card. This jumped the lowly 20MHz 68030 IIsi to a 80MHz PowerMac. I had planned on putting this 601 Processor Card in one of my IIci (a...

Hero System I pulled together the best of my working components and assembled a hero unit. I went with the Echo logic board because it looks clean and doesn't have any bodges. I put in four 2MB RAM SIMMs, to get the system up to 9MB. Then, I selected a clean non-yellowed case, picked a good...

Software Slows Things Down I've reached the point in this project where I need to get the software squared away. As usual, this slows things down. I don't want to give the wrong impression — this is so much better than it used to be, thanks to the great work of so many in our community. The...

I suspect he means “In Real Life.” As in, not an online thing.

The more I read about the Macintosh II, the more it seems like an engineering experiment. It is amazing how well they iterated and improved by the time the IIci came along.

It is amazing how something so simple makes the difference between working on a board and walking away from it.

Charlie is Copacetic Charlie was working well after the recap, except it would not properly shutdown with Caymac's Power Up IIusi replacement PSU. I followed the power signal on the PSU's pin 9 (J15) back to the Egret chip, a 68HC05, at UB1. The connection seemed good, so the issue was either...

Bravo is Beautiful Bravo is the system I've worked on the longest (technically, I started working on it in 2021), and it is finally good to go. It's last problem was bad serial communication. TechStep was reporting a Serial Communication Controller test failure. Most specifically, it said...

Alpha is A-Okay After spending time on Bravo's audio problems, I decided to check out Alpha's speaker problem while the subject was still fresh in my mind. Alpha was working perfectly after I restored it back in 2021, but I was using it as a known-good system for testing, and along the way, my...

Back to Bravo Bravo finally has a voice. I went back to consider the odd oscilloscope readings I saw earlier, and I started at the beginning with the power going into the Sony sound ICs. Both were getting 4V. At first I wasn't sure what voltage they should be receiving, but I knew 4V seemed...

I suggest getting an extension cable with individual cables (like the one I have in the photo), and then use a hack saw to cut off the first ten pins that align with the Mac's power input jack. Be sure to check the orientation so you get the right pin alignments.

Yes, an 24-pin ATX power supply cable can be cut down as an extender for several ‘90s Mac PSUs. Here is one connected to a Mac IIsi.

What's next... I tested each of the five functional boards with my snazzy TechStep built by @max1zzz. It confirmed that Delta and Echo are working perfectly. Charlie tested fine, but it would not shut down with the new Power-Up-IIusi PSU (it works properly with the Magnetek PSU) . It was the...

The Dreaded Power Supplies Knowing how bad the IIsi power supplies are (due to leaky SMD caps on the soft power daughter board and leaky axial caps on the low voltage side of the main board), I decided to try the Power-Up-iiusi (Lucy) board that Caymac Vintage posted on Github. I realize he is...