Recent content by Mc128k

I did not add diodes, they were pre-built in the cable, an official "Apple Hack". They are for both protection and voltage dropping, I can't remember their type, but any rectifier I think will do fine, they don't need special features. They were the black type, not the glass ones.

Weird, I thought I had the first version. As you can see here, the two wires on the right are soldered together and they go directly to the board. I presume that if you had them separated there could be issues when the main battery was connected without a backup battery (the frying you were...

No, the wires are soldered together at the microswitch, any failure of the switch shouldn't impact this, the cables remain shorted.  They both give 6.5V from the lead acid battery OR the 9V battery when flipping the switch. The 9V voltage is dropped by two diodes on the wire.

Can you post some details on your workbench setup? How are you powering the mac? What voltage exactly? Using the original wires? The portable is a bitch with power control and regulation, most problems can be hunted down to incorrect usage I think.

Another thing, just to update the topic. The lead-acid cells have arrived and I reassembled the battery pack. It just works perfectly, so absolutely no IC/FET/Transistor was harmed during my awful experiments. So... it is done now. Everything in full working order, just like new. I also see...

About the floppy I would start a new thread, as this isn't related to power regulation. I haven't investigated on it, but if you follow the first scheme I posted you should be able to check if there is power first. 16-18 as you can read from techknight's posts is a hack that kickstarts the IC...

Also try to trace all components from the power plug to the transformer primary coil. I'm not an expert on this, but I suppose that if the power mosfet gets toasted every time maybe it's because it's drawing too much current, and that could be because it's not oscillating. Try to backtrace the...

I have a classic II that needed the recapping. It also happened that some electrolyte corroded a few VIAs and the board had to be lightly bent to make it temporarily work, so make extra attention to the damage BEFORE recapping, take some photos, these could come useful after. Also try to "divide...

Never followed any guide, I just made it up of pieces I found in the lab. Not-so-much-clean now, I just used it for the damn hard drive. Oh, the white brick works, I'll order the replacement caps anyway.

Guys, I was wrong. I have the white brick, and I'm going to use this of course.

Mine had a gray brick for sure, I just confused it with the others. Didn't know there was a white one. Or maybe it was a replacement

Hoping this could come useful, this is how I fixed the hard drive.

Don't worry, I just removed the heatsinks to check the fet temperature, they are back now. And it wasn't just the switch, when I first connected the lab power supply I attached the wire to the "end" of the switch, bypassing it. It was actually the entire cable that made the mac believe the...

FOUND THE ORIGINAL PROBLEM THAT WAS THE CAUSE OF EVERYTHING. The power cable. ...yep, corrosion does that too. The switch has some internal resistance. Maybe the wire too. I'll rebuild it from scratch. Likely the computer saw this as a rapidly-discharging battery.

The hard drive had a leaky liquid from the border and a rotten rubber near the magnets. Opened in my homemade clean room, removed the goop and cleaned with alcohol, replaced the rubber with tape, sealed with hot glue. It works beautifully. About the serial port, it was the rightmost, and it...