This small battery operated PIR light was drawing excess current in standby mode, runnning its batteries flat very quickly. The fault was interesting and unexpected.
Given the continuous standby current of 10mA at 4.5V I wondered if the rogue component dissipating the power would show up on a thermal camera. It did, and more interestingly it could also be detected by probing with a cheap thermocouple.
Ironically, desoldering the faulty component also made its fault clear, suggesting perhaps a moisture ingress issue.
A link to Mike's epic Flir E4 teardown. https://www.youtube.com/watch?v=NtqUE67BUDI
If you enjoy my videos you can support the channel with a dollar for coffee, cookies and gadgets at https://www.patreon.com/bigclive
Given the continuous standby current of 10mA at 4.5V I wondered if the rogue component dissipating the power would show up on a thermal camera. It did, and more interestingly it could also be detected by probing with a cheap thermocouple.
Ironically, desoldering the faulty component also made its fault clear, suggesting perhaps a moisture ingress issue.
A link to Mike's epic Flir E4 teardown. https://www.youtube.com/watch?v=NtqUE67BUDI
If you enjoy my videos you can support the channel with a dollar for coffee, cookies and gadgets at https://www.patreon.com/bigclive
About your thermal camera; In the words of the Joker talking about Batman's "gizmos" :
Where… does he get all those wonderful toys?!?!? 😂
After the hack of the Flir E4, what model does your Flir equal now?
Wow, 12 deg C inside your working space there? an average of 26 degrees C in my lab 🙂
If you were surprised about the thermal camera picking up the temperature difference, then go sit down on a chair for a few seconds, then get up and point the camera at it! Hint: butt cheeks!
We all hate SMD components, they weren't designed for mortals anyway, but for pick and place machines. I would just toss a pig tailed through hole ceramic cap on it and gloop it down to keep it from flapping around in the breeze.
BC…nice catch using the FLIR! I've caught problems which had hot-spots by using thermal indicating film simply laid on the board. I wonder if a (much less expensive) LASER pointer type of thermometer might have been similarly useful… as you note, I expect heat of desoldering probably cured the cap…of course, who knows for how long…china's finest at work! …pretty poor practice though, by the FLIR manufacturer, to hide features! Cheers
For testing loose surface mount components blu tack is your friend! It was a tip I picked up from Eugine Trundle's TV servicing handbook years ago as a way of replacing surface mount chips in-situ.
That multimeter… horrendeous! 😀
If the capacitor is a Tantalum, a common failure mode is the formation of microfractures, which cause local heating which in turn causes a local chemical change in the tantalum ceramic material, causing it to become conductive, then more heating, more fracturing and finally catastrophic failure.
FLIR camera reminds me of the Potterton EP2001 two program (5/2 day, weekday/weekend) central heating timer. That model could be "converted" into the much more useful full 7 program model (separate programs for each individual day of the week) simply by the addition of a hidden internal wire link on the PCB. Obviously the more advanced version (with "platinum plated" wire link pre-fitted at manufacture, of course) had a significant price premium. Luckily a piece of copper wire works just as well…..
Hah, just did a video on a very similar problem on a pocket balance. That one drew 40ma on standby! Sadly it wasn't a bad cap in my case, on a viewer suggestion I took the board down to just the single IC blob but had no success.
Stop… Have a rest for a bit Clive. your doing it for you don't forget.
I just watched your electronics basics video. Very well done! Its amazing how many people have videos out there but never take the time out to explain the basics. Its funny how we use the dirty diddys to remember capacitor band colors. I remember doing something simular in my ham radio classes. We did something like that for the periodic tables too. Helps you remember stuff. I cant remember any of that stuff any more,but it did help as far as passing a grade.
Ah, so this is what Low Equivalent Series Resistance really means…