An issue I noticed from my inspection of the Main power chip, an LTC3456, is that the PWRON pin and the RESET pin are not going high? According to the datasheet I believe the PWRON pin is meant to stay HIGH to keep the Chip on after the power button is released. When the button is held pressed down, everything seems to function normally around that area. All inductor voltages seem fine and stable. No capacitors appear to be shorted. But I get no signs of life on the device.

I am unsure where to move to next, would anyone have any suggestions on where to test next?

• I think the bottom left section of the board photo is for communication so I have not tested there thoroughly.
• I could not get a reading on the 'crystals'? in the CPU area with my oscilloscope.
• The CPU's gold pins on the topside of the chip had corroded and some are missing.
• There was a general spread of blue corrosion on the board when it worked fine, which I cleaned with IPA %100.
• The 2 wire jumpers are to supply power from a bench power supply.

I have an oscilloscope, multimeter, soldering iron and a hot air station.

Any help is greatly appreciated thank you.

Thank you.

LTC3456 Datasheet: https://www.analog.com/media/en/technica...

Power Circuits:

The full board:

LTC3456 Datasheet pin functions

⟐ Edited by author июля 29, 2026 at 16:35 GMT-7

I accidentally put 12v on the 5v usb power lines of my Car GPS, pretty sure its this model. But now the devices does not power on. I have taken it apart and am trying to locate the issue if it is visible, but I would like some help finding where to begin?

The first components after the power supply I cannot identify, I think it is a QFN 6 pin labelled 'JHE', then a SOT-23-3 labelled 'WEG9I'. I have listed the voltages below, but nothing seems out of the ordinary from what I can tell.

The power button reads 3.13v on one side and GND on the other.

The board:

Any help or guidance would be great, thank you.

⟐ Commented мая 30, 2026 at 13:22 GMT-7

I have cleaned the terminal but nothing happened

⟐ Commented мая 06, 2026 at 14:11 GMT-7

Thanks,

⟐ Answered апреля 21, 2026 at 16:06 GMT-7

Thanks, James

⟐ Answered марта 10, 2026 at 21:20 GMT-7

It will only turn on when plugged into the car, my PC or a USB charger, then it works OK.

I’ve left it plugged into a USB charger for over an hour, but it still won’t turn on unless it’s plugged in.

Can anyone suggest a fix ?

⟐ Commented февраля 22, 2026 at 16:58 GMT-7

were to fix it?

or is it better to get a new one.

Thanks for the help

⟐ Commented февраля 03, 2026 at 23:24 GMT-7

⟐ Commented декабря 12, 2025 at 2:26 GMT-7

⟐ Answered ноября 15, 2025 at 13:41 GMT-7

Thanks,

Can you help me?

Thank you so much.

⟐ Answered сентября 18, 2025 at 14:35 GMT-7

⟐ Commented сентября 08, 2025 at 21:41 GMT-7

⟐ Answered августа 21, 2025 at 6:29 GMT-7

thanks

⟐ Commented августа 19, 2025 at 5:09 GMT-7

Thanks.

⟐ Commented августа 11, 2025 at 2:46 GMT-7

My TomTom Go 620 Aussie model is about 2 years old and the battery is dead, so therefore I need to replace the battery. I have found the battery replacement video on YT for this model, but it’s the US model which has a couple of screws at the back of the GPS to be screwed out. On my Aussie model, there are no visible screws that I can find anywhere? The only thing I can find is what looks like a pry slot on the bottom of the GPS between the screen and the main body. Any help or ideas would be appreciated?

Cheers,

John

⟐ Commented августа 05, 2025 at 15:05 GMT-7