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Thanks for sharing that. Both my II and IIx had the same problem. C6<->R3 also goes to R18 on the II, so putting a wire between R3 and R18 is convenient with both on the bottom side of the board. On the IIx, it's R19 instead of R18.

I'm curious, which trace did you fix? I wasn't aware of a common problem with a trace on II's and IIx's and it would be helpful to know.

A possibly relevant thread on modem vs printer ports

Personally, I feel the performance differences between 68k macs are lost in the rounding error of 25 years of computing advances. However, from a technical perspective, the 650 is going to have significantly better memory bandwidth, particularly with interleaving. The maximum RAM is much...

The bright yellow axial on my II is located at C6. It's 10uF 16V.

By default, in System 7.1 (and probably others), the .Sony driver's VBL task is scheduled every half-second. One of the things it does is check for disk insertion or ejection via the eject pinhole, which involves addressing the drive, putting it into sense mode, reading status, and switching...

Oh, so here's the joy of using MAME. MAME hard codes the list of ROMs, their names, and their checksums/sizes, etc. And with each release things are added, changed, and rearranged. Also, MAME ROMs are not standalone. They have parent/child relationships in the sense that the parent ROM has...

FWIW, the latest pimame includes mame4all. The pimame thing is just a customized raspbian image. I'm using that on my arcade setup. I'm also using bunches of pi's to run my own cable tv setup. I run openelec on them with composite out, feeding into agile modulators that put each pi onto it's...

Nah, I'm good thanks. I'm going to wrap up my Plus keyboard project first before getting distracted by another project. ADB is on my list, I just need to complete a couple other things first. I've got the documentation I need for ADB, and I think the same board as the Plus keyboard project...

Personally, I'm a huge fan of the old NTI KVMs. The pre-USB NTI KVMs support Sun, PS2, and ADB keyboard/mouse, including translation between each. There doesn't seem to be a whole lot of information about them online, so I put up what I figured out on my Old NTI KVMs page. You can use either...

For the capslock key, the led is off when the keyboard is powered up. If you press the capslock key, the led comes on. If you press it again, the capslock key turns off. And so forth. The controller does have 5V tolerant IO, but I was not having reliable operation when the uC needed to bring...

I originally worked entirely with jumper wires like this: To actually assemble all the pieces onto the perfboard and have it working took maybe 20-30mins? I made a mistake on the first try and had the clock and data lines mixed up on the mac keyboard side, and once that got sorted out, it...

I'd be happy to help anyone that wants to build one. In the link up above I tried to list the parts and how to build one. The board I used has its own programmer built in, so there's nothing extra there. I used a template from someone else (based on someone else's template, based on ST's...

FWIW, the Turbo601 uses its own ROM 4MB. It doesn't patch the running ROM like the Turbo040 does. My best guess is, it's based on the same one apple used for their 601 upgrade for the 040 PDS. And the Turbo601 ROM lacks support for the SE/30.

Ever since I got the pile of compacts without keyboards or mice, I've been on the lookout for keyboards. Most of the keyboards I see available are going for about as much as the whole machine, so I haven't picked any up. Finally, I gave up and decided to make an adapter that allows using a PS2...

Here's some photos of my conversion of a dual 800k SE to an SE/30 I did a couple years ago. More here In this case, there was no cutout for the SE/30 PDS slot, which wouldn't matter if you didn't have any expansion cards. The power connector cutout was also too far forward. I hacked up...

I replaced those caps on the back of the LCD with TDK CGA5L1X7R1V335K ceramics and it seems to work well. I replaced them on 2 of the displays and both are now working normally. I didn't recap the 3rd yet, it's delaminating . I completely recapped all 3 logic boards. 2 chime, but only 1...

I've looked at doing the keyboard a bit, and it's a little more involved than just putting key codes out on a serial port. It is my understanding the 8049 has an internal non-reprogrammble ROM. There's a pin to hold high telling it to use an external ROM for development. So for our uses, we'd...

The logic board should have letters on one side and numbers on another, so you can identify regions of the board by the intersection of the two. The locations I gave below should correspond to this grid system. One non-destructive test you can do for the memory is to just overlay a suspect RAM...

The leading 04 indicates it is a memory test failure. It is my understanding that the subsequent digits are a bitmask identifying which chips are bad. Typically you see just one bit set, so would hit something like 048000 for the chip located at G12 on the logic board. If you've got multiple...