Powers on, no chime, HDD spins but not consistently

Hello!

I got this iBook G3 Clamshell from the local hackerspace in my city. It had the "vinegar syndrome" on the LCD and I took it apart to replace it.

However, I realized that, even with a bad LCD, I should still get a Mac chime when booting. This one doesn't do it.

A few facts:

1. Charging light turns on and gets orange when there's a battery plugged in.
2. Battery seems to be dead
3. I took the laptop apart so that I only have the logic board, DC-in, headphones plugged in so I can hear the chime (I was also testing with composite out plugged to a TV) and an HDD without its cover, so I can see whether it is spinning.

With the battery plugged in:

• Sometimes when I try to turn it on, I hear noise on the headphones but the HDD doesn't spin. I have to force it to shut down. Charging light turns orange after shut down, when HDD stops.
• Sometimes when I try to turn it on, the HDD spins just a little and I hear a noise on the headphones indicating that the laptop powered off
• Sometimes the HDD spins and keeps spinning. The mechanical head moves to the middle of the HDD as if it was trying to read something.

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Without the battery plugged in, it's basically the same behavior, but the charging light never turns orange.

I also tried resetting the PRAM (cmd option P R), PMU (holding power, holding reset, holding control shift option).

Heck, I'm almost doing some kind of ritual like this to make it work lol.

I checked the super capacitor as mentioned in this video and it doesn't look leaky. There's nothing leaky or weird on the logic board btw.

Please help me.