Can this be repaired?

Hi all,

I have an 8 input 8 output SMS controller that I got the other day (expensive) I got it all configured spot on then I decided to short out one of the outputs (output 1) of which made a cracking noise. Now the output is staying permanantly on.

I am wondering if this is repairable as of the below pictures (see red arrow going to component with hole in) the component thats blown is labelled J3Y of which might be a transistor?

I am not sure if these kinds of boards can be hand soldered or even if its possible to get a replacement component with the limited amount of info i.e J3Y and no circuit diagram etc

The controller is a RTU5011, 8 input, 8 output SMS controller made by the Chinese company King Pigeon

The other relay controlable outputs seem to work fine still its just output 1 (the rest are 0,2,3,4,5,6,7)

I need all 8 outputs to do with it what I have planned.

Thanks

The surrounding circuit suggests a NPN transistor (e.g. BC817). A suitabel type can be selected, if knowing the output current specification.

FvM said:

The surrounding circuit suggests a NPN transistor (e.g. BC817). A suitabel type can be selected, if knowing the output current specification.

Click to expand...

I believe I have found the component here..

http://www.hz-dz.net/UploadFiles/2009527101530473.pdf

The chances of them sending me one from China are very slim however..

Do you have any ideas who might sell them elsewhere?

If I were to get hold of one of these do you think it is going to be easy enough to solder?

Im asuming using tweezers and tiny tipped iron might work?

Thanks

The said BC817 would be a perfect replacement, there are many others suited as well.

The transistor can be easily desoldered by heating and lifting the single collector pin first, then the others. Solder wick can help but isn't necessarily required. You mainly should take care not to overheat the board and lift of pads by pulling too much.

FvM said:

The said BC817 would be a perfect replacement, there are many others suited as well.

The transistor can be easily desoldered by heating and lifting the single collector pin first, then the others. Solder wick can help but isn't necessarily required. You mainly should take care not to overheat the board and lift of pads by pulling too much.

Click to expand...

Do you think it would only be this one transistor that would of blown if shorting it out at 12V?

Is the transistor you mention as of the exact specs of http://www.hz-dz.net/UploadFiles/2009527101530473.pdf ?

Im also wondering if you can help me out with a direct link to the transistor for purchase?

The transistor specification is very similar, but it hasn't to be exactly identical. It has to fulfill the current and voltage rating and minimum required current gain for your application. Suitable transistors can be get from an electronic DIY shop, or mail order and online suppliers in your region. The price of 10 is about a small postage stamp's equivalent.

Just google BC817...

FvM said:

The transistor specification is very similar, but it hasn't to be exactly identical. It has to fulfill the current and voltage rating and minimum required current gain for your application. Suitable transistors can be get from an electronic DIY shop, or mail order and online suppliers in your region. The price of 10 is about a small postage stamp's equivalent.

Just google BC817...

Click to expand...

thanks for your help...

is this the one?

NXP|BC817|TRANSISTOR, NPN, SOT-23, 45V | Farnell United Kingdom

and it will do the same as this..

http://www.hz-dz.net/UploadFiles/2009527101530473.pdf

Thanks

Hi,

The SMD code J3Y is for transistor S8050 There is no problem to put BC817 instead. There is almost zero chance the microcontroller to be damaged - it's connected to the transistor through resistor.

You can easy desolder and solder a new BC817 transistor using an ordinary soldering iron.
In fact, any NPN transistor with SOT23 footprint would do the job.
I think the transistor is only use for I/O purpose.

Best Regards,
Siong Boon

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