Quick electronic repair question

[JeremyZButler]

Hi there
I am a complete electronics novice, but am just hoping to get some advice as to whether this item could be fixable. The attached photo shows the inside of a charging cradle for a baby monitor.

A day ago the cradle stopped working. The brown mark you can see suggests to me that the component (I don’t even know what it is called) has fried itself.

I’d appreciate any advice as to whether I might be able to get this gadget working again or if it is fried altogether. Could it just be as simple as getting a replacement component from an electronics store and carefully soldering it into place?

Thanks for any advice. Happy to provide any specs that might be necessary.

Thanks again.

 

[wkrug]

Without measureing You could figure out nothing.

I think the component is a resistor.
The value of it You can get by decoding the colored rings on it ( Search for Resistor color code ).
Then Yo have to measure if that fits with the part.
Other components on the PCB that are conected to the resistor cea decrease the mesuring result!

That such a part will be hot is normal.
Any other part on the PCB can be damaged too.
Most You can figure out with an resitance meter and an diode tester.

 

[cowboybob]

The noted component below (R3) has been replaced with the external resistor (rather sloppily, IMHO) and

the replacement has obviously gotten pretty hot. A properly designed circuit would not normally over heat the components. Perhaps the baby monitor's battery is defective?

The replacement would appear to be a fairly low value. My guess is that it's intended to be a current limiter with a value of around 10 ohms (or less)..

As the charger has quit working, my second guess is that the diode (D1) may have also failed (too much current for too long) and its failure is the actual reason the charger quit working.

We also have no idea if the replacement resistor is the correct value.

I'd suggest that you remove the PCB from the case and see if you can give us a picture of the other side of the PCB, at a slight angle, so we can see if R3's value can be determined.

I should note that a resistor's size is generally a good determinant for assuming its wattage capability. No doubt the replacement resistor is probably a 1 Watt while the original is probably only a 1/4 Watt. It's also likely to be "burnt" looking, which will make it difficult to confirm it's resistance value. For the 1 Watt resistor to also be overheating is a sure sign of other problems.

The only way to determine if D1 is damaged is to test it. Do you know how to do that?

 

[Nigel Goodwin]

The noted component below (R3) has been replaced with the external resistor (rather sloppily, IMHO) and

Perhaps I'm been charitable? - but I suspect the replacement isn't 'sloppy', but deliberately done that way in order to remove the resistor from the PCB and place it in a much better ventilated position.

The fact that even though it's MUCH larger, and MUCH better positioned, yet still has burned up makes me suspect it was manufactured like that - I hate to think what happened with the tiny SM resistor used instead.

As for 'properly designed', that most likely isn't the case.

 

[cowboybob]

Perhaps I'm been charitable? - but I suspect the replacement isn't 'sloppy', but deliberately done that way in order to remove the resistor from the PCB and place it in a much better ventilated position.

Point taken, Nigel. I was in a bad mood day before yesterday... But in my defense, I would have straightened the resistor's leads to make right angles... .

As for 'properly designed', that most likely isn't the case.

Well, I interpreted this comment:

...
A day ago the cradle stopped working. ...

as indicating that the cradle had at least been working for a while (who knows for how long).