PowerBook Duo battery replacement

[finkmac]

PG&E?

power management controller, also known as "EverWatch". it speaks with the batteries and also the charger.

 

[jmacz]

View attachment 83792

power management controller, also known as "EverWatch". it speaks with the batteries and also the charger.

Ah thanks. Didn’t realize it’s referred to as PG&E

 

[Arbee]

PG&E is the official name in the SuperMario stuff, among other places. "EverWatch" was the marketing name because they didn't want to get sued by the actual PG&E (Pacific Gas & Electric).

For the record, the "Sound controller" in that motherboard photo is actually the VRAM

 

[Arbee]

I saw a note from @bigmessowires regarding how it didn't boot from the rebuilt pack until he had stuck it in the dock for a few minutes first. This actually is similar to behavior I initially saw with a rebuilt battery for my PowerBook 540c. In that case it was related to the PRAM battery. If it's dead or not charged, my 540c didn't want to boot from the battery. Once I replaced the PRAM battery, it worked fine after that. It's possible that putting the Duo into the Dock charged the PRAM battery enough for it to boot from the main battery subsequently?

Having a good PRAM battery is important since the PG&E power manager's firmware is kept in the same battery-powered SRAM as the PRAM. When that goes dead the power manager is stuck with a tiny 512 byte bootstrap where all it can do is turn on the main CPU and hope it downloads a complete 32K firmware image.

Putting it in the dock (or just on a charger) should suffice to let it do the firmware download, which takes 10-15 seconds.

 

[jmacz]

Having a good PRAM battery is important since the PG&E power manager's firmware is kept in the same battery-powered SRAM as the PRAM. When that goes dead the power manager is stuck with a tiny 512 byte bootstrap where all it can do is turn on the main CPU and hope it downloads a complete 32K firmware image.

Putting it in the dock (or just on a charger) should suffice to let it do the firmware download, which takes 10-15 seconds.

This is good to know!

 

[mdeverhart]

Also, the keyboard interfaces with the PG&E, so the soft power button above the keyboard doesn’t work if the PRAM battery is dead and the Duo hasn’t been booted since being reconnected to power. In this case, the power button on the back of the Duo can be used to force power on, which will allow the PG&E firmware to be downloaded by the main CPU. From that point the soft power button will work until the power is removed (charger disconnected and main battery dead/removed). Note that the PRAM battery is rechargeable - but it will probably need a rebuild if you haven’t done that yet. I posted about my PRAM battery rebuild here:

Post in thread 'Duo 270c - Yay or nay?'
https://68kmla.org/bb/index.php?threads/duo-270c-yay-or-nay.38012/post-411863

 

[jmacz]

Cool. Yup, already rebuilt the PRAM battery as I had done the same for my 540c. Note I am not hitting the boot issue, I was just commenting on an earlier question in this thread by someone else.