Video payload no longer turns on with batteries

[sten]

Hi,

So we had everything set up and working for the video stream on Tuesday, June 12. During the bench test that day, our batteries died. We were instructed to power the video Pi using the USB mini cord and the modem with the power box, which we did, and things seemed to be working fine.

Today we plugged in the fully-charged batteries into the video payload and we could not get anything to power on.

We did some trouble shooting and found that it is not the switch and we can still power things on using the cables. 

Did we fry the board that the batteries plug in to somehow? Has this happened to anyone else?

[Skylar MSGC]

Do you have a multimeter that you can use to test the voltage levels on the pins from the powerboard. I would recommend NOT unplugging the cables just so you don't plug it in backwards on accident. There should be enough space that you can reach the pins with a multimeter. The voltage coming out of the pi power pins should be 5V.

Have you tested the voltage on batteries? They chould be sitting around 4.15V - 4.2V when they are fully charged.

When you are bench testing I would recommend that you use a hardline power source so that you aren't just draining your batteries in a testing senario.

[Skylar MSGC]

Also make sure that your batteries are plugged into the Pi and M5 plugs on the power board.

[sten]

We're grabbing a multimeter now. We're currently streaming using the hardline setup to illustrate that things seem to be fine and the batteries are the issue.

So when we get the multimeter, we should measure right at the Pi input with the battery plugged in?

I forgot to mention earlier, but if we use these same batteries with the still image payload, the still image works fine. Maybe it is a voltage issue then as the still image as the shunt jumper set to 5V mode whereas the video as it set to 12V (we didn't change anything, though, and the video used to work with just the two batteries...)

Thanks for the responses and I'll be on the call.

[sten]

We measure 4.2 volts from the batteries, but only 1.8V coming from Pi_POW when the batteries are plugged in to the Pi and M5 plug ins.

[Skylar MSGC]

So the part that might be the issue for your board is the ptn04050cah. Here is the datasheet for that

www.ti.com/lit/ds/symlink/ptn04050c.pdf

[Skylar MSGC]

imgur.com/XdwmYiw

[sten]

Skylar,

We applied 4.2V with a DC power supply to the spots you indicated in your picture. We got the same 1.8V coming out of Pi_POW.

What's the next step?

Thanks a lot!