Search results

Okay, so I'm an idiot. Turns out probe sensitivity matters a lot. Lesson learned. By switching from 1X to 10X, the picture becomes much clearer. Y2 output: C32M: So the replacement oscillator Y2 is indeed putting out a full 0-5V swing. It overshoots a bit, but that seems fine? The real...

Thanks, I have done a lot of fiddling with UH7. It's socketed, because those pads were just too impossible to solder directly, like you said. I tried reflowing the socket pads, cleaning and re-tinning the pins on the PLCC... no luck. I am hoping the heat is just a side-effect of the CPU being...

New oscillators came, no change or improvement. The C32M line at pin 1 of UI7 still looks very wrong - it's the correct frequency, but a triangle wave from 3.2-4.3V which is definitely not TTL levels. So I still suspect something is still wrong with the clock generation, perhaps UH7? I also...

I desoldered Y2 from the board and tested it directly with a 5V bench supply. The results are very similar to the in-circuit plot from before. The leads were too short to stick in a breadboard, so I couldn't set up a proper test circuit. But connecting 5V, ground, and the output directly should...

Here's the C32M line, measured from the output of UH7 at R28. It's pretty sad-looking.

It sure seems like 1.120V is not low enough to trigger a logic low, since the specified threshold is 0.8V.

Thanks, I checked both of these things. I even asked my wife, who has experience with electronics QA, to look it over. No improvement, unfortunately. And the analog board recap went smoothly but did not change anything. I dusted off the scope and began poking around, starting with the...

That would be quite the undertaking. It would be really difficult to price them low enough to make it worth the cost of parts and time. I think it would have to be a labor of love for someone with ample free time.

Yup, that is what I found as well. I realized that I did not recap the analog board yet, so that is the next step.

Actually, pin 5 on the floppy connector is N/C, so that was a red herring. Currently, there is startup chime or display at all. I did find and repair a couple cold solder joints on the analog board, but no improvement there. I'm pretty stuck at this point.

I measured the -12V line at -11.7V at the power supply connector in-circuit. So the power supply is working, but the bad reading at the floppy connector still might be a clue.

I recapped the CR-44 power supply with the kit from Console5. All went well. Thank god for the Hakko; I got it done in just 90 minutes. Here are the output voltages, unloaded. No major changes. Color Before Recap (V) After Recap (V) Green -8.11 -8.22 Red 13.48 13.51 Orange 5.33 5.32...

Well, that was short-lived. A little later I plugged in a keyboard and mouse, and now it won't boot. The failure was gradual. The screen and audio started wigging out, and now the display won't come on at all, and certainly no startup chime. There was some high-pitched squealing that might have...

It's alive!!! Thanks again to everyone for all the help to get to this moment. Will continue reassembling and testing, but what a milestone.

Oh my god… a gold star for you. Thank you so much for finding that. And joevt, you happened to find the one post on the entire Internet from the friend of mine who encouraged me to take on this project. I fixed up that SE in the background of his photo. :)

Almost there! Just waiting on 128 MB RAM to come tomorrow. I had major success removing the CPU with the Hakko FR-301 after preheating it with the heat gun. The CPU came right out, only pulling a few pads. Thanks Callan for the tips! For the floppy D-sub, I used the Hakko for the pins, and...

So while not directly related to the topic at hand, I have a challenge that isn't addressed in Volume I: designing windows using ResEdit. I understand how to lay out a DLOG using DITL, but can I also use DITL to lay out controls for a document WIND? Is that even standard practice, or are window...

Progress is slow, but steady! I finally worked up courage to tackle the PLCCs. A Redditor suggested sockets for the 20-pin PLCCs which made it immensely easier, because the pads are just too far underneath the part to solder them directly. The other PLCCs have transferred over just fine - a lot...

Success! I wrapped up the example code, added a few styling options, and published the code on AmendHub for others to utilize as well.

Perfect, thank you! It took me a while to locate the first edition, I think because the second edition was way more popular? Anyway, for future reference: First edition ISBN: 0201156628 Second edition ISBN: 0201608383