PDQ power plug voltages

[dobbs]

Does anyone know the expected voltages on the power plug terminals of the Powerbook G3 PDQ? I measuring at the internal solder joints of the plug with the laptop disassembled.

My PDQ has decided not to power on at all. Usually when I plug in the power supply the laptop’s LED lights briefly and the fan might twitch, but it’s not even doing that now.

The story so far:
I was attempting to build a replacement PRAM battery, which I think I succeeded at. I had it to the point where I reassembled everything, it booted up and everything worked great. Except I had misaligned one of the expansion bay eject mechanisms. So I disassembled it again, fixed the alignment and reassembled it. Now it is inert.

I’ve tried the usual debugging methods, removed all extra devices, reseated everything several times… Wondering how to debug this thing on an electrical level. The voltages I’m reading on the power plug are something like +/- 0.8V, which doesn’t seem right.

 

[A24A]

Which exact power adapter are you using? Apple power adapter model number, if applicable? Check the power adapter label/text for output voltage and current.

One would expect 24 V at the power plug terminals. Please note that the special barrel-type power plug is different. See also, for example: https://68kmla.org/bb/threads/pin-out-m7783-power-supply-duo-230.40402/post-529953

 

[dobbs]

Which exact power adapter are you using? Apple power adapter model number, if applicable? Check the power adapter label/text for output voltage and current.

One would expect 24 V at the power plug terminals. Please note that the special barrel-type power plug is different. See also, for example: https://68kmla.org/bb/threads/pin-out-m7783-power-supply-duo-230.40402/post-529953

Sorry, I did not receive a notification for this reply.


This is the power supply I’m using. I understand there are two M7332 yoyo-style adapters (I have both) and this is the one that fits.

Your link looks interesting, I’ll see what I can probe from the male side of the barrel jack.

However, this power supply works on my G3 Pismo, so I’m pretty sure the PSU itself is fine. I was hoping there were known probe points on the Wallstreet’s power board or mainboard that could tell me something useful.