Recent content by Garrett B

What accelerator do you have installed? I recall having this same behavior with my Performer clone... never could get it to work right. Freezes, bus errors, random crashes, etc.

When you get the black screen, is this with onboard video or a PCI video card? I am currently only able to get video out using a PCI card, and am curious what your setup is. I may have similar memory issues!

The CPU runs at 16MHz on these cards regardless of what processor is installed on the Performer board. Having a 40MHz marked CPU is nice but it’s still only going to run at 16MHz…

Yes it's the overclock causing trouble. You can use an emulator like Basilisk to install onto the disk image you're using. You could also revert back to stock 25MHz speed to do the install, then try the overclock again. Easiest thing would be to install from a modern computer, then reinsert the...

I've used a Dremel tool with a thin cutting disc attached. Work your way around the case slowly and you should be able to reattach the top fairly easily!

If it's booting and just has no video, I'd check the Molex plug that's on the logic board, specifically continuity of video signals that go to the AB. I have found a break there which resulted in the exact thing you show.

I don't have one yet, but am strongly considering it. Troubleshooting boards would be much easier!

Is this what you're looking for? https://androda.work/product/vga-adapter-for-macintosh-portable/

Wow... great catch. I just confirmed by looking at an original photo and decoding the color bands. I have parts to build a neckboard of my own but haven't started yet. Guess it's time for another DigiKey order!

The board itself is clean (no corrosion), and I did insert/remove the headphone plug a few times to see if that might clear things up. No luck. I guess next step is break out the multimeter and see if the contacts are closing inside the connector when headphones aren't connected. This is where...

So "no sound" might be a stretch - there's no sound coming from the internal speaker. Headphones play just fine. I have tested the speaker itself, and even tried installing a different version of Mac OS hoping it was a software issue. What's weird is that there isn't even a startup chime, so I...

C6 looks a little funky... I'd check it out to make sure it isn't shorted. Wouldn't want to have anything blow up the first time you try things out.

Nice work diagnosing the RAM issues! If it were me, I'd remove the accelerator and make sure the logic board will get you to a flashing floppy disk. That way you know the majority of the logic board is in a working state.

You bring up a good point here. I've done some serial diagnostic work on a Portable but didn't even think to try the IIsi. I know it's supported - just need to figure out syntax for the right tests to run. Unfortunately a lot of this isn't super well documented. I'll post back though when I have...