USB bluetooth transmitter/receiver dongle

[ginoleonardo52]

This is a usb to bluetooth transmitter
or just a usb stick that lets your desktop have bluetooth
it's broken i'm trying to diagnose it with a multimeter but
have no idea what most of these things are
the led is broken it doesn't light up anymore
the pc is able to understand what this device is when i plug it
but it doesn't light up anymore and it doesn't give the pc bluetooth.
It use to give a icon of a bluetooth on my desktop but now
it does not show that icon on my desktop and doesn't transmit or receive.

 

[rjenkinsgb]

The CSR IS in the middle looks to be a "BGA" package device.

Those have a grid of connections on the underside and that style of package is a common cause of failure, any flexing, or just too much thermal expansion and contraction, can cause some connections to fail.

You need specialist equipment to work with them..

I can't see the exact IC type number, but underneath it looks something like one of these devices, possibly around 30 - 40 connections from looking at some other CSR bluetooth ICs:

You can go over the other component joints, & traces to check for cracks with a magnifying glass, but if there is nothing to be found, it's likely that it is that BGA device that's lost connection.

ps. The CSR IC is a computer in itself, with a Bluetooth radio system built in. The other IC near it is probably its program memory. The RAM & everything else is in the main IC.

 

[ginoleonardo52]

This is news flash for me I didn't know BGA ball grid assembly. Thank you so much for clearing some of these components up. I was thinking about changing the resistor on the back of the transmitter to see if that led will fire again if not i probably just have to change the LED and the CSR chip?

 

[Nigel Goodwin]

This is news flash for me I didn't know BGA ball grid assembly. Thank you so much for clearing some of these components up. I was thinking about changing the resistor on the back of the transmitter to see if that led will fire again if not i probably just have to change the LED and the CSR chip?

The LED not working wouldn't affect the operation at all - you could remove it, and it would still work perfectly - it's merely an indicator of what's going on.

Why don't you just buy a new module?, they are cheap - and you're almost certainly not going to be able to source spare parts for this one, bearing in mind even if you could source a similar chip (assuming that's the fault?) then you most likely would have to program it as well.

As you've never even heard of BGA, then you obviously won't have the required equipment, or expertise, to replace one - I certainly don't, although I do know someone who does (it cost him a few thousand pounds though).

 

[ginoleonardo52]

Yeah that's true it's definitely cheaper to just buy a new dongle but i'm doing this for learning purposes. I'm still looking at buying a 3 in 1 soldering station kinda on the fence about it but yeah it's just learning.

 

[Nigel Goodwin]

Yeah that's true it's definitely cheaper to just buy a new dongle but i'm doing this for learning purposes. I'm still looking at buying a 3 in 1 soldering station kinda on the fence about it but yeah it's just learning.

You're not going to learn anything worth while trying to repair something like this - and a cheap 3 in 1 soldering station isn't what you need for BGA replacements.

If you want to learn from repairing things, then choose items with have schematics available, preferably through hole, and spare parts - and specifically spare parts than come ready programmed (if required).

 

[ginoleonardo52]

So if I was to theoretically buy the CSR chip there's no guarantee that is pre-programmed so it might just fail even if its soldered correctly. If so then i'm guessing the manufacture has that pipeline for these chips and assemblies already mapped out?

 

[Nigel Goodwin]

So if I was to theoretically buy the CSR chip there's no guarantee that is pre-programmed so it might just fail even if its soldered correctly. If so then i'm guessing the manufacture has that pipeline for these chips and assemblies already mapped out?

Any programmable chip usually comes blank - and the purchaser programs it to do what they want - or they provide the code to the chip manufacturer, who makes them ready programmed (this is known as 'mask programmable').

I would imagine just buying a chip is almost certainly not going to contain the correct code for your device.