Author Topic: Extremely corroded TIC --> need advice  (Read 296 times)

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Offline Flukav

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Extremely corroded TIC --> need advice
« on: June 22, 2020, 03:42:34 pm »
Dear all,
I acquired through classified an Axis Q1941 in «excellent condition» at low price. 10 days later, I received what looks like wreck, but a working wreck.
Opening the unit shows extreme corrosion on both mechanical parts made of aluminium, electronics and... optics.
A layer (protective) seems to peel of the 60mm germanium lens, while white spots stains the protective window.
Even the aluminium casing had swollen under sever corrosion and a white dust covers almost every single part. I presume this unit was on a dock or something close to the ocean.
I need your advice on how to restore this camera, which displays a clear image, obviously not much affected by the optics condition.


Online Fraser

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Re: Extremely corroded TIC --> need advice
« Reply #1 on: June 22, 2020, 04:36:05 pm »
My first thoughts would be to send it back for a refund as that Camera could best be described as water damaged, and at worst, scrap, for parts only. The fact that it is working truly amazes me   :o

That camera does not appear to have suffered normal minor water ingress or condensation damage. It looks more like it was submerged in sea water and plenty got inside the casing. Hence why I am amazed that it’s PCB tracks carrying power gave not dissolved away.

I have worked on a lot of merchant marine equipment that has come from salvage yards. It ranges from perfectly OK , just needing a clean, through to total corroded junk. The problem with water ingress, especially salt water, is that it causes corrosion of the PCB tracks if power is applied at the time of ingress. It does not take long to do a lot of damage. PCB vias and IC legs just corrode away ! Having repaired Ex sunk HF radio gear I know that the equipment continues to suffer water ingress related issues long after it is repaired. If it is a salt water drowning, you really need to strip the boards of all components, or the IC’s at the very least, clean them thoroughly in an Ultrasonic bath and then leave the PCB in a special salts extraction solution that draws the salts out of the PCB material. Failure to remove any salts that exist in and on the PCB can lead to future corrosion related failures. That is, of course, if future reliability is a concern. If the water damage is purely rain ingress, the stripping of the PCB is not needed and just a good clean in a swept frequency ultrasonic bath containing distilled water is often enough.

Any component that looks to have suffered corrosion needs to be removed, carefully cleaned, inspected, tested (where possible) and re-soldered to the PCB. Any part of the camera found to be damaged should be repaired or replaced.

Now to the optics and microbolomter....... neither appreciate submersion but your lens objective is showing evidence of such  :'( The Lens coating is a bit of a mess to be honest. There is nothing that can be done by a hobbyist to repair that damage. You need to disassemble the optical section and inspect the elements fir damage. It is likely the other lens element(S) suffered corrosion related harm as well. The AR coating that is flaking away can flake off on the internal lens faces and get onto the microbolometer window or Interfere with the FFC flag mechanics. The Microbolometer may have suffered corrosion or staining of its window. It’s leads may also be corroded and any socket used for it needs to be carefully inspected for corrosion. Disassemble the FFC Flag assembly and its motor/solenoid and inspect for corrosion.

In short, this is a very involved restoration project that far outweighs the value of the camera in a commercial world. If it was cheap and you want the enjoyment of the repair, like I often do, it is worth the effort. Do consider carefully whether you want to dive down this particular rabbit hole though  ;)

« Last Edit: June 22, 2020, 04:44:13 pm by Fraser »

Offline Flukav

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Re: Extremely corroded TIC --> need advice
« Reply #2 on: June 22, 2020, 06:39:05 pm »
Thanks for this extended reply.
To send it back, I wished, but the dealer claimed I «voided the warranty by opening the camera»: smart girl.
For hobby use (ie look for wolfs in the mountain this winter), it can still be a nice item for 220€, given it has a 30fps for 388 pixels output and already a long-range lens, in poor shape though.
I'll get some isopropyl alcohol tomorrow, distilled water, and a new soft toothbrush. I'm mostly scared of shorting the FPGA pins with leftover dissolved salt drying.
Won't alcohol destroy electrolytic capacitors by drying their gum? On this blog some people mentioned good old WD-40 to protect corroded PCB.
We have to give it, Axis make some reliable devices... too bad the only seal becomes brittle under sun exposure.

Offline james_s

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Re: Extremely corroded TIC --> need advice
« Reply #3 on: June 22, 2020, 07:00:21 pm »
I'm astonished that it works, that is some nasty corrosion on that PCB, I would not expect it to be reliable.

Did you pay by credit card? If so you may be able to get a refund that way. To claim that you voided the warranty by opening it is pure BS, the damage was obviously there, how else are you supposed to see it? You should post the seller so we all know not to deal with them.

Offline SilverSolder

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Re: Extremely corroded TIC --> need advice
« Reply #4 on: June 22, 2020, 07:12:44 pm »

The item is not in "excellent condition"  -  it is not as described, and they have an obligation to take it back.
« Last Edit: June 22, 2020, 07:14:21 pm by SilverSolder »

Offline railrun

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Re: Extremely corroded TIC --> need advice
« Reply #5 on: June 22, 2020, 07:34:04 pm »
If you are planning to clean the PCB you should watch some videos from Louis Rossmann. Before cleaning you should resolder all points.
But if you had paid with paypal I would open a dispute and upload the pictures.
It‘s just a question of time until it will stop to work.

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