Search results

Here's a link to my final IIsi PSU daughterboard replica design on GitHub. Feel free to do whatever you want with it; most of the credit goes to Bomarc honestly. I just did some sleuthing to figure out a few things Bomarc didn't, and fixed a couple of errors in their reverse engineered...

Thank you! The Bomarc schematic (which is fantastic and I heavily relied on for this project) has a few mistakes so it will be nice to have a fully correct schematic available for it. Thanks! I remember seeing your pictures of the two revisions while I was doing all my research. Very...

Update: My IIsi power supply riser board recreation project is pretty much complete. I soldered up the first one today using a stencil, solder paste, and hot air. (Added the two big caps afterward by hand). All parts on it are brand new from Digi-Key except for the obsolete ones: M51977FP (eBay)...

Ahh I see, I misread their explanation and missed the part under 7.1P2 where they said: Control panels "exercised" (opened and closed) during Custom Mac process.

Volume 3 has a restore for the Quadra 610 DOS Compatible (694-0268-B). It only includes a DOS 6.2 image though, no Windows. I do like the little caption in the Get Info window: "DOS for the rest of us".

Very interesting! I had noticed that note about compression in the past, but didn't think about the consequences of it in terms of preservation. I'll have to play around with different OS versions. I restored the 7.1P2 version for the Performa 450 from Volume 1, but I didn't find that the...

Thank you for your incredible effort to preserve these rare CDs! You likely have one of the very few remaining copies of this series in your possession. And it's complete! Thank you so much for your generosity of sharing these images with the entire community! As an example of the things you...

I haven't had time to tinker further with troubleshooting, but I thought I'd share the progress I've made on a IIsi power supply riser board recreation. This is probably the weirdest PCB I've ever laid out. I took a picture of the original and then traced everything on top of it. The pad and...

Because I'm crazy, I cobbled together a IIsi power supply tester. Probably good to have anyway if I'm planning on designing a replica riser board. It'll help me test and calibrate a new riser board without potentially damaging a motherboard. I just used a 20-pin ATX extension cable and cut it...

I wonder if mine sometimes briefly powering on and right back off when I initially plug it into AC power is a clue? That seems like it could potentially point toward some interaction between /PFW and the standby power, since I would think the caps would be fully drained at that point. I...

Here's a closer look at /PFW and +5V when the "turn back on" happens. (They're both perfectly overlapped so you can't see the marker for +5V, but it's yellow). The turned-off 5V rail has only dropped to about 1.2V when it powers back on. /PFW has gradually crept its way right to about the same...

Awesome and congrats! That's a clever way to put on the 10k resistor, I like it! I just want to be clear that I have no idea whether this 10k resistor is a good long term mod to make, or if there might be any bad side effects. I was mostly just doing it for diagnostics to get a feel for where...

Had a chance to look at this further. Agreed that this section of the circuit involves audio. I see a lot of 12V and -12V rail triangles in the schematic at that point. I'm still at a loss here. The "45" transistor is only involved with turning the power supply on or off. When it's on, the power...

Oh no! Sorry to hear that! I'm on a lunch break so I can't look in detail until later tonight, but I can't imagine that resistor would cause this problem. All that pulldown should do is tweak the value of the existing pulldown resistor built into the 45 transistor, effectively requiring /PFW to...

Haha, not a solder blob! :D Yeah, it's a little variable resistor or pot or something like that. If I'm reading my notes correctly, mine measured as about 2.106 kohms out of circuit, but I'd need to double check that before saying it confidently. Bomarc's schematic says 2K which makes me wonder...

Nice! Good point -- seems like those would have lower ESR than the originals, so that kind of blows my theory in the water. I do wonder what would happen if I put slightly lower uF capacitors on my 5V rail for fun. Or, I wonder if I have a leaky component that's feeding a little bit into the...

It's very subtle and I probably should have marked it better in the pictures. If you look at the voltage rail connected to C103 and R103, it's different before and after. On Bomarc's schematic, it goes to the triangle with just a single horizontal line which is labeled as "primary circuit...

Thanks for the data points! How are you able to measure that high of capacitance? Do you have a specialized meter? I've noticed my multimeter can't measure larger capacitors too. My multimeter just says OL, and my cheap DSO-TC3 component tester just hangs up forever if I try to measure the...

I believe when /PFW goes all the way up to 5V, it means Egret is driving it high in an attempt to turn the power supply on. When it goes to that 4V-ish level, it means the power supply is on but Egret has it set as a Hi-Z input and is not driving it at all. So it just gets pulled up to 5V minus...

Wow, you went above and beyond! Thank you so much! (Nice choice of scope, too. ;)) My tests are with an actual hard drive, no PRAM battery. Extra data point: I just realized that if I don't have a hard drive plugged in, my IIsi logic board is also not capable of turning off my IIci's power...