Recent content by David Cook

One more thing when you get home from work. Confirm that you hear a sound from the floppy drive during test step 5 SWIM test.

I got my reproduction TechStep from @max1zzz during the following thread: https://68kmla.org/bb/threads/recreateing-the-apple-techstep.41293/ You could reach out to him to see if he has a newer version of Vol. 4 tests or whether his is better at entering test mode for some reason.

What have we learned? Your CPU is working. Your ROMs are good (checksum passed). Your bus is working (memory and ROM tests). Your CUDA is working (crystal, PRAM, clock, power on, and ADB tests). That's why the TechStep is saying it doesn't recognize the CPU. The id has been changed from LC...

I am testing my LC 520 board in my Color Classic using the reproduction TechStep. ADB mode works for me. 1. Mac power switch off. 2. Plug in all cables to TechStep 3. Mac power switch on. 4. Power up TechStep 5. Choose LC520 6. Choose 3. TstMde It turns on the Mac as though the keyboard power...

By the way, have you plugged headphones into the jack to see if the bong is playing through there?

Absolutely fascinating @JDW! This is good news. The TechStep results indicate most of the board is confirmed working. I wonder whether something is wrong with the edge connector. Let me run my 520 board against my TechStep and see if my results are the same.

A different Color Classic came with its instruction manual. It includes a brief insert that calls out the power-up sequence. There must have been enough customer confusion to warrant Apple drawing attention to it. What's odd about the power-up sequence in this period of all-in-one Macs is...

I just repaired another Portable that was crashing when sound played. I decided to put this board in my ultrasonic cleaner. Afterwards, the hybrid module was dead. That's okay -- as I was just experimenting to see if I could get it to last. I replaced the module with a modern part, per usual. I...

It might just be a bad joint (your solder joints seem good). I've had capacitor gunk get under a leg and eventually disconnect when exposed to mechanical stress or temperature changes.

I agree with @Fizzbinn that it is more likely that something simple went wrong with the board in storage (or when being jostled during insertion) as opposed to the 575 frying the board. With power off, but a battery installed, check pins 3 and 4 of the CUDA with an oscilloscope to make sure the...

With the motherboard removed, do you measure a short between +5V and gnd on the motherboard?

It sounds like you have short between +5V power and ground. Do you have any tantalum caps?

Cool! Thank you for the confirmation.

Thank you. Yes, there is definitely a black-ball mouse prior to the low-power version. I assume yours does not have this symbol on it:

To avoid hijacking your thread on the PowerBook, I've updated my journey to find the Portable mouse here: https://tinkerdifferent.com/threads/black-ball-adb-mouse-serial-numbers-and-portable.5047/