USB Pinout for Charging - Page 1
Forum section: electronics / repair

author: vidarr
author_rank: Frequent Contributor
timestamp: March 14, 2025, 11:45:54 am
content: Hi, I'm trying to fix my wife's bluetooth speaker. The problem is the USB micro? male end. There was a connector mounted to one of the boards and it corroded and the pads came off. So, tried soldering a wire to what I was sure is the positive and a wire to the negative (which I am 100% confident is the negative).When I plug it in, nothing happens. It should charge.Attached is a pic of where I attached a wire to what I think is the positive. I attached the negative wire to the underside of the board. The negative is solid --I tested the ground on multiple points around the board.My question is, are both the center pads for the positive? Because the outer two pads are definitely negative/ground. This connection is 100% for charging with USB cable. There is no data going to the speaker thru this connection. There is another USB connection for data.Thank You!

author: benj38
author_rank: Frequent Contributor
timestamp: March 14, 2025, 03:29:20 pm
content: This does not look like a mini or micro USB connector since it has only 4 pads instead of 5.The only USB connector that has 4 pads is the full-size Type-A.https://en.wikipedia.org/wiki/USB_hardware#Pin_assignmentsIn any case, all USB 1.1 to 2.0 connectors have the +5V and ground as the two external pins, whereas the middle pins are for data (and ID for the 5 pin versions).Later versions of USB have many more pins and are thus obviously not what you are looking at.In short, if this is any kind of a USB connector than the middle two pins arenot"the positive"!It may help if you take a picture looking into the business end of the charging cable that comes with this speaker.

author: vidarr
author_rank: Frequent Contributor
timestamp: March 14, 2025, 08:43:16 pm
content: I un-soldered the usb jack before I took that pic. The original 5 pads are shown here in the photo. I marked the two missing pads in red.It seems that the five pads get condensed into 4 pads in the circuit. You can see the 5 pads, then it goes to 4 pads then there is a capacitor and resistor, and another capacitor and resistor. This leads me to believe that it gets condensed down to 2 lines in. Each line gets a resistor and a capacitor. It makes logical sense, I guess, but I have no idea.Check the pic.Thank You!

author: vidarr
author_rank: Frequent Contributor
timestamp: March 14, 2025, 08:46:27 pm
content: See on the circuit board how there is a bracket around the left two pads. Then, there is a bracket around the right two pads. Maybe the left 2 pads are + and - and the right two pads are + and -That is my best guess.

author: benj38
author_rank: Frequent Contributor
timestamp: March 15, 2025, 09:05:55 am
content: OK, these new pictures finally make sense.As I already wrote, the +5V and GND pins are the two external pins in the row of 5 pins.https://en.wikipedia.org/wiki/USB_hardware#Pin_assignments

author: vidarr
author_rank: Frequent Contributor
timestamp: March 15, 2025, 08:19:38 pm
content: Yes, thank you, I got it to work using the 5 pads. The thing is, I was hoping to solder to one of those 4 pads because they are bigger and look like they will last a lot longer than those tiny slivers that the 5 pads are (two already missing).One of those 4 pads is a ground. The other three I can't figure out. It's ok though, I got it working well enough.THANK YOU!Also, I didn't know this was a Harman product until I opened it up and saw all the labels. My wife has had this speaker for almost 20 years. It has lasted longer than all of the other bluetooth speakers by far. Other than those two pads corroding, it is a solid product and still sounds awesome.