Shorts on M92T36, replaced, still no signs of life

New to doing this.

I took the switch apart, and tested for shorts. There were shorts around the M92T36. I replaced the chip, and shorts went away.

I plugged in the amp meter on the USBC and there is no draw. Amps read 0.0. Turned the plug over, 0.0. With battery disconnected, all the same, 0.0. With battery still disconnected, I get 5v at the m92t36. I also get 5v on the USBC pins. The fuse is good, and the coil is good.

I am not getting anything on the screen of the switch, and no response with the power button.

I was wondering what the next step should be. I was thinking about changing the BQ chip. Any advice?

Thank you

1 Like

Are you getting voltage at the BQ chip?

There is no voltage DC on any pin of the BQ chip. What am I missing here…

Thank you for your help

Also, I show no shorts around the BQ chip. All capacitors test normal.

I would check to see if you are getting votage out of the M92 / arriving at the BQ. If nothing it getting there I would take another look at the M92. If it is getting there, then I would probably start with BQ next.

1 Like

First thing I would check is the USB port itself which is a common cause of M92 failure. What is your open circuit battery voltage. If the battery is pretty much fully drained the BQ may not see that it is connected. You can externally charge it with one of the TP4056 USB chargers while disconnected from the switch. Karl

Before I saw this, I did just that. it was slightly out of alinement. adjusted, and boom, it works. all charged up and ready to pay. Thank you

Nice! Good job! Glad you sorted it :slight_smile: