How to factory reset dead Apple iBook G3/366 (Firewire/Clamshell) to sell?

Without power to the iBook, the only way to erase/wipe the internal hard disk would be to open the computer and remove the drive. This is not quite easy. You may find details if you search for the computer model and something like disassembly or replace hard drive. The removed hard drive can then be connected to a universal USB bare-drive adapter, which in turn would be connected to the USB port of another Mac (or PC, with the appropriate software) for wiping.

It would be easier with a working power adapter. If you take a look at the text on the M7332 (a magnifying glass may help), you will find that it has a DC output of 24 V at 1.875 A (max) = 45 W. It has a 9 mm outside diameter DC plug. This is a special plug (with an internal pin that looks like a 3.5 mm stereo plug), not to be confused with a standard barrel-style plug. You may be able to find a used power adapter via an online auction site, but the condition would be unknown.

A normal/universal power adapter with a 24 V DC output (at approx. 2 A) with a standard barrel DC plug cannot be used directly. A special adapter piece converting a standard barrel plug output has been known to exist (a web search for something like 9 mm iBook DC power plug adapter?).

Have not tested one, but the 9.0 x 3.5 mm connector/adapter on that page at least looks like a suitable model.

The 2 A stands for 2 Ampere. That is, the output current the power adapter must be capable of handling. A higher output current rating of a power adapter (for example, 3 A) should be OK, but never a lower.

24 V DC = 24 Volt DC. The output voltage must be 24 V DC, and nothing else.

You will probably find a number of (stabilised) universal power adapters. Sometimes with adjustable Volt settings. Often with exchangeable tips. Check that the Volt setting is 24 V DC. Double-check the polarity at the output barrel tip. It may be wise to use a multimeter to test voltage and polarity before connecting anything. Double-check the input polarity of the special connector/adapter.

When you connect the charger's cable to the DC-in port, do you see a green or amber glow around the port? You can find a number of replacement chargers at ebay, including this one. If the DC-in board's power port is damaged or there's an additional problem with the internal circuitry, you've wasted your money. Unless you're absolutely sure that the internal hard drive contains no files with personal data that could be used for identity theft, I wouldn't consider selling it as-is.

This YouTube video and the followup video concern a power ON problem with a clamshell iBook, that was determined to be caused by a leaking capacitor on a circuit board. I don't know if you're experienced with removing and soldering a replacement component. If not, you could sell the iBook as non-working unit. the video does show the steps needed to access and remove the hard drive. Because plastics stiffen with age, you have to be quite gentle when removing the keyboard surround, to prevent cracking it or the catches that secure it in place. I hope this helps you.

If you remove the hard drive, it could be connected externally to another Mac via a USB adapter (like this) and erased with a security wipe. The IDE-to-USB adapter is not a Mac-specific piece of hardware, so you can purchase one from a number of PC retailers.

Unfortunately, internal access to the DC-in board would require disassembly of most of the computer (try a web search for something like disassembly ibook g3 dc-in).

If you use a magnifying glass and take a close look inside the special 9 mm DC-plug barrel, you will notice that the 3.5 mm "pin" resembles a standard 3.5 mm 3-pole TRS headphone plug (https://en.wikipedia.org/wiki/Phone_connector_(audio)). However, the "pin" in the special DC plug is a few mm shorter. In this very special DC plug, the tip (T) of the "pin" is not connected, the ring (R) is negative (-), and the sleeve (S) is positive (+24 V). This is an unusual pinout. The problem is also that access to the ring (R) and sleeve (S) for testing is extremely difficult without causing a short circuit, because of the surrounding barrel.

Based on the above, it may be possible for a knowledgeable technician to use a standard 3.5 mm 3-pole TRS headphone plug (https://www.amazon.com/Fancasee-Replacement-Connector-Headphone-Earphone/dp/B07Y8KGJKL/ is merely an example) connected to another DC power source. An extra plastic distance would be needed in order to make the effective plug length equal to that of the "pin" in the special DC plug. This should allow a 24 V DC supply directly to an iBook G3 Clamshell for temporary testing purposes, using a universal power adapter or lab power supply instead.

Yes, the aforementioned 9 mm outside diameter x 3.5 mm DC plug was a special Apple model. There was a smaller one (7.5 mm outside diameter with a 2.5 mm inner plug/pin) as well for later iBook models.

If a tip adapter for the conversion of a standard barrel-style DC plug to the special 9 x 3.5 mm cannot be found, another solution will have to be used.

First of all, are you sure that the existing M7332 is faulty? Unfortunately, it is almost impossible to measure the power adapter's output voltage (due to the protected design of the DC plug) without access to the DC inlet jack in the computer.

One should perhaps not rule out the the problem could be in or near the DC inlet circuits in the iBook G3 Clamshell itself.

If necessary, you would have to look for a second-hand original M7332 power adapter (make sure that it is one with the larger DC plug!) via an online marketplace/auction site.

Alternatively, if the power adapter actually is faulty but its DC cable and DC plug are OK, it may be possible (for someone with electronics expertise and soldering skills) to use the latter two and a suitable standard barrel-type DC connector in order to make a special adapter piece. This would require exact information about pinouts.

Because that leaking capacitor was on the underside of the logic board, you'd have to remove it for a complete inspection of any damage. Additionally, de-soldering and re-soldering can be a real headache, if fluid from a leaking capacitor has corroded the area surrounding its location. Given the value of a G3 iBook, I wouldn't recommend paying someone to diagnose and/or repair it. I'd remove the hard drive and e-cycle the iBook or sell it as a non-working computer for parts. You could connect the hard drive to another Mac via USB and check for any files of interest, before erasing it.