Classic Green Light

[fizzyboy]

Hi I have a GO Classic with the Green light ON when Charging but wont Switch On .Can anyone Tell me what it is and how to Fix It !

 

[Pedro2NR]

Try to reset it with a pin

 

[scoutdubna]

TomTom910 Battery

Hi I have a GO Classic with the Green light ON when Charging but wont Switch On .Can anyone Tell me what it is and how to Fix It !

Just because the green light is on doesn't mean that the 910 is charging. In fact it almost means nothing at all. First thing to check is - rubber gromit - is it missing. This helps to force the 910 forward to make a good connection. Second thing is to clean the contacts. I tried using something like a green washing up pad but didn't work. Used switch cleaner and problem solved. Could be the battery but try other things first.

CHRIS

 

[Edmo117]

Green Light of Doom!

I managed to get the dreaded Green Light of Doom on my TomTom One. Being a retired aerospace electronics engineer ....with too much time on my hands...I decided I had nothing to loose by taking it all to pieces and trying to fix it.

And I DID!!....not bad for a old guy!

The problem was caused by the car charger. From the charger are 3 wires going to the TomTom socket.

1) The RED wire is the charging voltage nominally 5 volts.

2) The BLACK wire is the 0 volt return wire

3) The WHITE wire is the voltage sense wire.

When the white wire gets damaged, as mine did, the car charger gets noi feedback from the TomTom as to how the battery is doing and so keeps ramping up the voltage it applies to much more than 5 volts. I suspect it goes all the way to 12 volts and this is what causes the problem.

My unit actually had smoke coming out of it when it went POP...that's bad enough but I could not get the smoke back in!

The smoke was caused by the destruction of D8 ( a small black rectangular thing 1.7mm long by 1.3 mm wide just behind the charger input socket). Consulting the data sheets for the chips in the unit I figured this to be a 5.6 volt Zener diode. Anyway that is what I have replaced it with and it all works OK so far.

As well as this device, I had to replace the main power control chip. In the case of my TomTom One it was a Linear Technology LTC3455EUF. This cleaver little chip does everything for the power side of things including charging the battery.

Replacing this device is not easy and should not be tried by anyone who is not 100% confident with surface mount devices and their replacement and has all the kit to do it with. If you have a friendly electronics lab or assembly house in your area it could be worth asking them to replace it.

Anyway, that fixed it for me....thank goodness!!

If anyone needs photos or advice please feel free to cotact me.

Good luck

 

[Larry L]

Any idea why/how the White wire got damaged? Do you think it is a design problem or build problem?

I wonder, have you read the open unloaded voltage of the car charger to see how high it will go? I would be nervous if it can go to 12V (13.8V for most).

I have been using other USB chargers with no problem, I wonder if I am pushing my luck. I think I'll have to measure their open voltage now.

 

[PC4]

R18 Zener

Edmo117,

In what directions must i solder this zener please because burning out

 

[Andy_P]

PC4.... a few points for you....
Firstly, this topic is over three years old, so it's fairly unlikely you'll get a reply from the specific person you've asked.

Second, can you confirm which model you are trying to fix? (This topic started on the Go Classic and moved on to one of the TT ONE models.
All of these will have similar charging circuitry but the exact layout on the PCB is very different between models, so you need to be more specific about which one you're dealing with!

Next, you've headed your post with "R18 Zener". I'm assuming you've taken this component reference number from the PCB? Well anything prefixed with an "R" is likely to be a resistor, not a zener diode.

Finally if you search the various TomTom forums such as this one, PGPSW, YourTomTom (and there are several others) using the search terms "zener" OR "diode" then you'll find several pictures of the diode mounted on the PCB on various models.