Pinnacle MovieBox DV power polarity

[Les Bradley]

I recently obtained a Pinnacle MovieBox DV at a hamfest here in Baltimore, but it lacks the power supply. I found information that it requires 3.3 vDC, but I have not found a reference to whether it wants to see center positive or negative on the plug.

Anyone have an old unit lying around that might reveal the polarity info?

Thanks -- my first post!

[Arpatle]

Maybe you can get the information on the circuit board.

[Les Bradley]

After looking around on the Internet unsuccessfully, I tried that -- took the covers off, hoping to find some indication of + or - to no avail. I wonder if 3.3 volts is small enough that I would not destroy a chip if I tried and got it wrong, but I don't want to risk that yet!

Thanks, Les

[Les Bradley]

I just talked to an engineer. He says that a way to find out if a device needs center positive or negative for its power supply is to compare impedances between, say, the ground of an RCA jack and the two sides of the power receptacle. The side that shows the lower impedance will be the ground side.

I haven't tried it yet, but sounds like it should work.

Les