Flir Vue damaged board

[rodri_e]

I am working without ‘hands on’ and only from your picture so please do consider my comments in that light and make your own decisions based upon the readings you are seeing in tests.

What I consider is that you've done an amazing job identifying things in the board just by looking to the picture! (It's very good picture, isn't it?  ).

So I woke up to read the forum and straight to the testing table. I do have now a regulated 5V/500mA source to use. I'll do that in a few and post back but before I buzzed out the two missing pins on the HR4nC. The one on the top right corner, just beside the ground pin, goes to RSTb pin on the CP2012, I guess as a way to reset the chip when the USB is plugged in. The other one, on the top left corner, has a small trace through what seems to me as a diode (I'm not very good at identifying these ones) and to ground. If it is a diode, it's shorted cause it buzz to ground. This may give us and idea of what kind of LDO the HR4nC is.

I am uncertain of the function of those large annotated video and power pads on the PCB. There is the possibility that they are both outputs to accessory boards with the Power pad actually a supply to accessory boards rather than an input to the camera. I honestly do not know.

I agree they must be outputs to accessory boards. At the beginning I thought those were simply test pads because they are connected to the corresponding pins in the USB connector: main power, ground, Video L and Video H.

I'm attaching a new picture with the components removed and the board cleaned.

[Fraser]

Hi,

Sorry I have to be quick today. The small component you mention is a resistor. These can be Zero Ohms so a resistor reading short circuit is often just a zero Ohm one as nothing higher in value was needed

A current limited 500mA power supply MAY struggle when the camera first boots as that involves operating the FFC flag and the current can rise to 800mA.If the camera refuses to boot or appears to boot loop, it could be due to the lack of current capability in the power supply.

Fraser

[rodri_e]

Hi, Fraser. I hope you are enjoying your weekend. I am not. I have very bad news. I powered the board with my 5V/500mA source through an amp meter and both the main PWR input and the power rail after the HR4nC consume less than 10mA. Good. So then I plugged the board to the module and powered it again. 0mA. That's when I realized there is also a short in the power rail of the module...  Since I was testing only the power/interface board I didn't realized it before but it buzzes between gnd and the regulated power rail when it is connected to the module. I had a quick check at the other boards but I can't see any evidence of additional damage so that would be very hard to trace.

I guess that leaves me with only one option: send it to Flir and expect a big bill and a couple of weeks in the whole process.

Thanks anyway for your huge help.

[Fraser]

Sorry to hear this.

I detailed the power input and DC-DC converter stages of the TAU core in my TAU repair post that I referenced earlier. There are basically a stack of DC-DC converters and one of them has likely failed short circuit at its input. I will revisit my repair post and see if I remember anything useful. There could be another TVS diode involved. They can fail short and still look visually normal. Sadly I am away from home so cannot refer to my TAU repair documentation.

All the Best

Fraser

[rodri_e]

I'm going to have some time this afternoon to go around the TAU core but it is a more challenging endeavor by far than my attempt to fix that interface/power board. Since there are no visual signs of damage it's going to be a lot harder to know where to look, those components seem smaller and closer and there are a lot more of them there. I haven't even been able to remove the ribbon cable that connects the two boards. 

I'm about to have access to a similar (not exactly the same) Flir Vue and was planning to proceed in a similar way you did with your TAU core; use the good one as a reference and maybe swap cards to see what works and what doesn't. Are those boards that interchangeable or there is something I should look for first before swaping? (like revision number, versions, camara resolution or so).

Thanks again. I'll keep posting if I find something else.

[Fraser]

The TAU does use high density pcb’s And very small components. It is challenging to remove and replace components unless you are used to working on such densely packed pcb’s And have the appropriate equipment. A steady hand and very fine tip in the soldering iron are essential.

It is possible to substitute PCB’s but always consider the risk of doing so as boards with shorts can damage a good board that is providing the power.

If you have another thermal camera then I have a possible helpful idea. You need an adjustable constant current power supply. If you do not have one, it might even be worth investing in one as they are very useful and some Chinese models are quite affordable. If not, try to borrow one.

Set up the working VUE camera with a monitor and correct power supply. Position it so that it can view the TAU PCB with the DC-DC converters on it. Power the damaged PCB from a 5V power supply with its constant current set to 200mA. Watch the working VUE camera display and look for a hot spot forming on the damaged PCB where the short exists. You may see PCB tracks warming up, discrete components or one of the chips. You are trying to generated some visible heat energy in the short circuit loop. The ground plane is large so it is likely that you will see the positive feed path into the PCB and can see at what point it stops, that being the location of the short circuit. A short in a chip can cause increased heat at that relatively poor conduction point. Resistance = heat If you cannot see anything with 200mA flowing in the short circuit loop, try increasing the current a little at a time but I suggest not exceeding 1A for safety and keep an eye out for any component in series with the short circuit loop that is getting too hot due to excessive current passing through it.

If your power supply folds back in the face of a short circuit across its output, you can try placing a power resistor of a few ohms in series with the supply to the damaged core. A 21W car light bulb is also a good choice in the absence of a resistor. It will light weakly at 5V and is capable of permitting a decent current draw in the damaged PCB.

Food for thought

If you can find the shorted component, you are able to disconnect its input pin and repeat a power on test to see if any more short circuits exist on the PCB.

Fraser

[Fraser]

Another test if you do not have another thermal camera to view the damaged PCB is to do the current injection as detailed above but, with the PCB cool, pour some IPA on the whole PCB and then apply power. Look for where the IPA evaporates quickest, or at all. That evaporation indicates heat generation and can lead to to a suspect area of the PCB or even the actual failed component in some cases.

IPA will not cause damage to the TAU powered PCB or components.

The flexible FPC ribbon cable from the Microbolometer to the the core PCB is fragile. To detach it you will need to release the ribbon from its PCB connector on the core PCB by either sliding the clip or lifting it, depending upon the design. The clip is very fragile !

Fraser

[Fraser]

In the attached images you can see the flexible ribbon cable PCB connector.

The brown ‘bar’ is carefully tilted up until vertical and this removes the clamping action from the ribbon.

In the first picture, the brown clamping bar is in the down (clamped) position and in the second image it is in the up position. I lift the bar using a jewellers screwdriver under the leading edge. Be gentle

Fraser

[1os]

greetings all on forum. Tau - 2 boards cannot be replaced from another camera.The Board recorded the number microbolometer. if you change the Board, you won't see the video. I have a power and data exchange Board. which you have is faulty. if you are interested in it, please contact me.I have a Vue pro configuration

[1os]

vue pro

[1os]

vue pro

[1os]

vue pro

[1os]

vue pro

[1os]

vue

[rodri_e]

Thanks a lot 1os. I just didn't get if it is or it isn't possible to exchange boards. I may be intrested in the Vue board. PM me with price to put it into my options.

[El P]

I have VPC module for Tau and it's very similar to your board. Mystery IC on my board has this marking: HR 4v C. So, 4v is most likely year/week. I think I found it: Diodes Incorporated AP2141. Power switch. Pin5 Vin - mine is 4.65v. Pin1 Vout same 4.65v. Switch. Pin4 is connected to ground with 0 resistor. Optionally, it can be connected to pin12 Suspend of CP2102. Pin3 is not connected on my board. Optionally it could (is connected on Vue board) to pin9 RST of CP2102. CP2102 has its own DC/DC converter inside - it provides 3.3v from pin6, CU45 pin5 gets 3.3v from there.

[Fraser]

EI P

Thank you for identifying the component that I mistakenly thought was an LDO 

Your identification is very useful to me as this component has appeared in other cameras that I have worked on but I never found its true identity and never had to test its function. Now I know what it’s function is I will store this information in my repair archive 

Have a Great Christmas 

Fraser