SMD Part Identification in FLIR identiFINDER R300 ZH

[RamEP]

Hello,

I've been working to troubleshoot some electronic and was wondering what this part is (circled in red)?  Thanks!

-R

[Twoflower]

I would say a 20mOhm resistor. I'm reasonably sure about that this is a resistor. But not sure about the value. It would make sense to have a low ohmic resistor close to the SMPS to measure the current. So if you measure a 'short' that's OK.

Maybe you should see to move (if possible) to the Thermal Imaging section here in the forum. To get much better support from there. Fraser seems to be very helpful. Also you should write what's the problem is :-)

[RamEP]

Hey thanks for the help on this, I did measure it and assume it was something else because it was coming up as a short.   The problem is with the IC nearby, the charging battery management IC however as a part of removing that IC, I was concern that I overheated that resistor component.   I swap it out just in case.

The unit is actually not thermal imager but a radiation detector FLIR makes.   Thanks!

[Twoflower]

Resistors are very tough. So I don't thing replacing that one will do any good but stresses the PCB and components even more. So if you can measure that there is a very small resistance on the terminals (or along the PCB traces) I wouldn't tough it.

[RamEP]

Thanks for the help.  It was indeed a low resistance capacitor I was able to measure it after subtracting out the resistance of the DMM leads and it came out to be around 20mOhm.  The battery now seems to charge fine after I had replaced the IC.  Now the harder part figuring out why CdZnTe detector isn't correctly identifying radioisotopes. D:  Hopefully it's just a calibration issue.

[RamEP]

It turns out that when I shake it, it seems to give spurious readings.  The CdZnTe detector maybe sensitive to vibration or something since it seems to have vibration dampening rubber.  I undid one sensor (3 gamma sensors) at a time and found out one of it is giving bad readings when shaken compared to the others.  CdZnTe detector is wrapped in copper foil  thats grounded and within it it looks like soft black silicone to further dampen vibration. I'm guessing its silicone given how soft it is and I used a soldering iron at 250C and it didnt seem to melt it.

I carefully removed the silicone and noticed two SMD had really weak soldering, it pulled off when I pulled on the silicone.  I'll solder it back on this weekend hopefully it'll resolve the sensor issue. (:

[Twoflower]

That doesn't look too promising! The big capacitor close to the HV notation (the brown component) on the PCB looks damaged too. The cracks are not normal. Looking at the picture while the potting is still there it is not damaged... And it is not easily possible to tell the value for that one. The size could be either the cap has a bit capacitance or a high voltage rating. The HV might indicate 'High Voltage' as well as the PCB design looks  a bit like that. But that's just an indicator. Without the schematics or a measurement of a working specimen it is impossible to say.

Also the resistor right close by looks strange. It is unusual to see the laser-trimming. If you look closely you see two white lines in the black. Either the top part is missing as well or the manufacturer of the module did a laser-trimming after mounting to calibrate the module.

About the parts that came off the board. I'm not sure what they are. It could be inductors which might make sense as they are connected in series on the PCB. Hopefully the copper coil was not on the outside of the part (like the first ones shown here: http://www.delevan.com/web/RFinductors/surfacemount/RFsurfacemount.html ).

[RamEP]

> The big capacitor close to the HV notation (the brown component) on the PCB looks damaged too. The cracks are not normal

Good eye!  I put it under the microscope and it looks like some sort of glue. 

> Also the resistor right close by looks strange. It is unusual to see the laser-trimming.

Is that what it is?  I did see those lines and I assume they're some marking however under the microscope it does look like it was cut.

> About the parts that came off the board

The parts were in tact when it was in the silicone and it didnt look like there's wiring.  The black dots on it were my crude witness mark in case they're directional for whatever reasion.

[Twoflower]

I would say the cap is broken. It looks very close to one of the pictures here. The material is kind of ceramic and very brittle. It is made of very thin layers of ceramic and conductive material. If it's damaged it easily creates a short between the pads. If you're desperate you can measure the resistance. If very high ohmic then you might be lucky, but a small vibration can trigger the short and who knows what happens.

The resistor cuts are 'normal'. This is done to adjust the resistor to the required value. It's normal if you have a ceramic carrier with printed on resistors (they need to be laser-cut to have the right value). Or on precission resistors, but I would expect that they are still cover them. Unusual for me but that is most likely not a big problem.

[RamEP]

> I would say the cap is broken. It looks very close to one of the pictures here.

I shot the photo using iPhone through a microscope so it's not as clear however if viewing through the microscope, I can tell it's not cracked .  Looking through the microscope with two eyes you can see that there's a thicker layer sitting on top.    If you noticed on the bottom , the "crack line" extends onto the metal portion.   

> The resistor cuts are 'normal'. This is done to adjust the resistor to the required value. It's normal if you have a ceramic carrier with printed on resistors (they need to be laser-cut to have the right value). Or on precission resistors, but I would expect that they are still cover them. Unusual for me but that is most likely not a big problem.


Quite interesting!

[Twoflower]

Maybe you're right. I only can tell from the pictures (thumbs up for the quality!). It could be a thin layer of the potting material. So maybe you're lucky.

[RamEP]

I'll get more time after work today I'll try to capture a more isometric view, it'll be more apparent I think

[RamEP]

It turns out that "crack" is silicone residue that was left behind, I was able to pick it up with tweezers.

Thanks for the help so far.  Going to get some silicone and put this back together and hopefully it'll fix the original issue.

[RamEP]

Place some silicone back in and waiting till it cures.  (( :