Identifying Blown Surface Mount Resistor (anyone have a BitFenix Recon fancontroller)

[WindowsXP16]

Alright I have this BitFenix Recon that my friend gave me, which is broken. Apparently he just plugged it into his pc and poof, smoke came out, he knows nothing so he gives it to me for keeping. I checked the damage and came to a conclusion that a SMD Resistor blew up, judging from the black char around it.

 

1) My main question is how can I determine this resistor value, the resistor is badly blown so I can't identify the number.

 

2) My second question is does anybody know where I can find the circuit diagram for BitFenix Recon or its PCB diagram. I tried to look in the internet but cant find anything. Or better yet if anybody have one lying around if they can bravely check the value of theirs so I can replace the correct value. The resistor is labelled R28 on mine.

 

Another note: The resistor is behind a soldered LCD panel so I haven't had a chance to check that side of the PCB, I am currently busy so I will have to leave that until the weekends to desolder the panel and further assess the damage.

 

Here are a couple of pics showing my problem:

 

edit: Title.

Edited March 19, 2018 by WindowsXP16
Change to a more apropriate title

[emosun]

it's probably the same value as the one right next to it.

 

[WindowsXP16]

Just now, emosun said:

it's probably the same value as the one right next to it.

 

The one next to it is a diode and a capacitor

[WindowsXP16]

Just now, WindowsXP16 said:

The one next to it is a diode and a capacitor

And the one across the diode is a smaller resistor.

[emosun]

i'll admit i 100% was guessing.

you could try a resistor that you know will be much more resistance then it needs and work backwards from there until the thing fires back up.

[WindowsXP16]

1 minute ago, emosun said:

i'll admit i 100% was guessing.

you could try a resistor that you know will be much more resistance then it needs and work backwards from there until the thing fires back up.

I guess that's one option, but I don't have a whole lot of resistor values to work with, I will see if anyone actually has an old one lying around where they can inspect the true value. But if it comes down to that I might have to what you said.

[emosun]

1 minute ago, WindowsXP16 said:

I guess that's one option, but I don't have a whole lot of resistor values to work with, I will see if anyone actually has an old one lying around where they can inspect the true value. But if it comes down to that I might have to what you said.

you could use regular style resistors and just bend the leads to touch the old contact points where the surface mount one used to be. 

 

you might be casting a very small net here trying to find someone who also has one of these as most people don't really do the external fan controller thing anymore.

[WindowsXP16]

Just now, emosun said:

you could use regular style resistors and just bend the leads to touch the old contact points where the surface mount one used to be. 

 

you might be casting a very small net here trying to find someone who also has one of these as most people don't really do the external fan controller thing anymore.

I will also post this in other forms just to increase the possible results.

[WindowsXP16]

A-ha, I thought of a great idea. I can just solder 2 wire leads connecting to a potentiometer from the broken resistor. Then I just set the potentiometer on high (say on a 10k potentiometer) and decrease the resistance slowly until the fan controller works again. Might not work but I will test this out.

 

Message me if this is a bad idea, otherwise I'm gonna try it and see if it works.

 

Thanks for the help.

[Unimportant]

1 hour ago, WindowsXP16 said:

A-ha, I thought of a great idea. I can just solder 2 wire leads connecting to a potentiometer from the broken resistor. Then I just set the potentiometer on high (say on a 10k potentiometer) and decrease the resistance slowly until the fan controller works again. Might not work but I will test this out.

 

Message me if this is a bad idea, otherwise I'm gonna try it and see if it works.

 

Thanks for the help.

Resistors don't just explode for no reason, there's probably more issues. I'd try to reconstruct the schematic myself by following the connections (with a multimeter for the traces you can't visibly follow), figure out what the circuit does and what could cause that resistor to blow, then test those things first before applying power again and possibly doing more damage.

 

The SOD80 diode next to it has a blue ring, those tend to be zeners. So it could be a crude resistor-zener voltage regulator, test the diode first.

[WindowsXP16]

11 hours ago, Unimportant said:

Resistors don't just explode for no reason, there's probably more issues. I'd try to reconstruct the schematic myself by following the connections (with a multimeter for the traces you can't visibly follow), figure out what the circuit does and what could cause that resistor to blow, then test those things first before applying power again and possibly doing more damage.

 

The SOD80 diode next to it has a blue ring, those tend to be zeners. So it could be a crude resistor-zener voltage regulator, test the diode first.

I will get on testing that in the weekends, but what should I expect if the zener diode is faulty?

Does it fail open or short?

And if it does fail, what possible problems can it cause as a voltage regulator?

 

I know its best to check and test it, but I don't have the time yet, I am also a novice in electronics but I do have some equipment.

[Unimportant]

7 hours ago, WindowsXP16 said:

Does it fail open or short?

And if it does fail, what possible problems can it cause as a voltage regulator?

Diodes can fail both ways.

If it goes short it could be the direct cause of the fried resistor, but the rest of the circuit might be fine because the short would prevent the rest of the circuit seeing any voltage.

If it fails open then the rest of the circuit would've been exposed to the full unregulated input voltage, with more damage probably done.

 

*if* it's a zener voltage regulator.

[WindowsXP16]

On ‎20‎/‎03‎/‎2018 at 3:52 PM, Unimportant said:

Diodes can fail both ways.

If it goes short it could be the direct cause of the fried resistor, but the rest of the circuit might be fine because the short would prevent the rest of the circuit seeing any voltage.

If it fails open then the rest of the circuit would've been exposed to the full unregulated input voltage, with more damage probably done.

 

*if* it's a zener voltage regulator.

https://www.newegg.com/Product/Product.aspx?Item=N82E16811997078

 

Looking at some of the reviews, people had the same issue as smoke coming out of their unit and not working.

 

I did some poking around the diode, it turns out that the diode is indeed faulty, I was getting a reading on the anode to cathode and in reverse using my multimeter in diode test mode. The diode failed in short I think, but I was getting crazy values when measuring the resistance across it, like 1.9M ohms. The anode of the diode is connected to the resistor in which you might be correct that the diode must have caused this.

 

I don't know weather its worth my time fixing it now, it probably has more problems that I think it has.

 

What do you think the problem is with the circuit based of the information? Or there isn't enough info and I should just chuck the thing out.

[Unimportant]

7 hours ago, WindowsXP16 said:

What do you think the problem is with the circuit based of the information? Or there isn't enough info and I should just chuck the thing out.

Not enough information. Perhaps that diode is worked a little too hard due to poor design and gets weaker over time until it eventually dies. But that is pure speculation.

[WindowsXP16]

6 hours ago, Unimportant said:

Not enough information. Perhaps that diode is worked a little too hard due to poor design and gets weaker over time until it eventually dies. But that is pure speculation.

yeah I gave up upon it, I threw out the pcb but kept the mounting bracket, I could use my Arduino to make a fan controller from scratch. Thanks for the help anyway.