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Electronics => Repair => Topic started by: luis.v on December 27, 2014, 04:15:40 am

Title: Repair of Garmin Nuvi 50 - Battery Charging Issue
Post by: luis.v on December 27, 2014, 04:15:40 am
Hi! I tried to repair this nuvi 50 GPS for a friend of mine. At first, I tought it was just a simple battery replacement, but seems to be the battery charging circuit on the main board, because it works with USB power on, it works with another full-charged battery connected to the board but doesn't work with the discharged battery (the original battery was tested and is OK, it was only discharged) until connected to the USB Power which the charging icon appears but doesn´t charge the battery. I need help identifying the two semiconductor components near the battery connector, the transistor like 052R3 and the HDW 2SAA which I think are involved with the battery charging. Voltage Readings without battery are

1- 0V
2- 0V
3- 0V
4- 5.25V
5 - 4.4V

With Battery ON

1- 3.7V
2- 3.7V
3- 3.7V
4- 5.25V
5- 4.4V

   Something is not switching, anyway, thanks for the replies!! :)
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Title: Re: Repair of Garmin Nuvi 50 - Battery Charging Issue
Post by: Zepnat on December 27, 2014, 05:00:52 pm
If it works with a new battery but not the original surely the battery is simply worn out

Edit. Does it charge the new battery?
Title: Re: Repair of Garmin Nuvi 50 - Battery Charging Issue
Post by: luis.v on December 27, 2014, 05:18:12 pm
Hi!, no it doesn't. That's why I suspect the charging circuit is failing. I believe that 4.4V spot over there its the battery charging voltage, but I'm not for sure.
Title: Re: Repair of Garmin Nuvi 50 - Battery Charging Issue
Post by: tautech on December 27, 2014, 06:47:25 pm
Take a look at BZX84 series Voltage regulator diodes for the SOT-23.  :-\
Title: Re: Repair of Garmin Nuvi 50 - Battery Charging Issue
Post by: NiHaoMike on December 28, 2014, 04:17:49 am
You can add your own charging circuit. I suggest looking at simple one chip solutions.

Another possible cause is the OEM making the charging circuit check for an OEM charger as a way to prevent third party chargers from working.
Title: Re: Repair of Garmin Nuvi 50 - Battery Charging Issue
Post by: amyk on December 28, 2014, 03:57:10 pm
HD W is a Vishay SiA811ADJ (http://www.vishay.com/docs/68955/sia811.pdf)
052R3 is probably a Vishay (http://www.vishay.com/docs/72763/72763.pdf) but I can't be bothered looking through all their SOT-23s.