Go 520 charging problem - SOLVED

gpspcb · Occasional Visitor Joined: May 01, 2007 Posts: 18

Wow, it seems like it's a massive problem, dubbed The Green Light of Death! Mostly caused by the wrong type of charger being used it seems.

If anybody is good at electronics, can you take a look at this picture and tell me if the diode is the right way around please. (don't laugh at my big blobs of solder! Rolling Eyes

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Sorry about the size. Needed to be big!

The fact that it's charging in the car now suggests it is, so I don't want to play around with it but, I've looked up diodes and I'm a bit worried because the line on the diode indicates the cathode side which supposed to permit a negative through it, but, you can see on the circuit board a +ve sign.

mikealder · Posted: Sun Sep 25, 2011 11:40 am Post subject:

You have put the D5 diode in the correct way around, I have just checked a scrap 720 thats never had a soldering iron near it and the white stripe on the end of the diode is next to the + sign printed on the PCB - Mike

gpspcb · Occasional Visitor Joined: May 01, 2007 Posts: 18

mikealder · Posted: Sun Sep 25, 2011 12:06 pm Post subject:

What usually blows D5 clean off the PCB with as the component overheats is when the voltage feedback sense wire breaks in the car charger lead, this results in the car charger putting out whatever voltage is applied to it from the ciggy lighter socket (usually about 13,8V) its rare to fix a device after this as its often more than D5 that gets blown.

For some reason the D5 in your device looks to have been poorly soldered in the first place letting it drop off the PCB, not something I have ever seen before, good result though in getting it fixed - Mike

Andy_P · Posted: Mon Sep 26, 2011 12:18 pm Post subject:

Excellent fault-finding and an even better result!

Normally, this sort of exercise ends in "Yes, I can conclusively say where the problem lies, but it's all fried!"

As Mike says, it's very odd to find a component misplaced, but working (unless you have changed the battery and dislodged it yourself!).

And I'm still surprised at how it could work with a PC connection and not the car charger!
_________________
"Settling in nicely" ;-)

gpspcb · Occasional Visitor Joined: May 01, 2007 Posts: 18

M8TJT · Posted: Mon Sep 26, 2011 6:42 pm Post subject:

Andy_P · Posted: Mon Sep 26, 2011 6:53 pm Post subject:

gpspcb · Occasional Visitor Joined: May 01, 2007 Posts: 18

Brad99 · Occasional Visitor Joined: Apr 12, 2008 Posts: 11

Electronics engineer speaking here.......... I bet your diode got so hot it desoldered itself. It happens.

Jaz666 · Posted: Sun Oct 09, 2011 6:34 pm Post subject:

I'm glad I found this thread.

My 540 started to run out of power and shutting down whilst plugged into the original charger in the car.
I put it down to the battery wearing out, so replaced it.
That didn't improve things, so tried a new Tom Tom charger, no improvement.

Like the OP, when fully charged, it will run for 4 hours before dying again.
It will charge from the Car Supply, but only when switched off.

I had already concluded that something on the charging circuit had gone, but now it seems I know what to examine on the board.

Maybe I'll get a fully functioning device again before the Winter Weather arrives Razz

SargFowler · Occasional Visitor Joined: Jan 07, 2015 Posts: 1

An old thread, but there's a lot of these SatNavs out there.

On my TomTom, C133 had melted and gave loads of black soot around the components. I've replaced this, but the tracks on the board got torched.
I think C140 connects to C133, so I've put a wire between these and all seems good so far.

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