![]() Depending on the ruggedness of the ATMEGA die and the current limit of the voltage regulator, this may or may not cause permanent damage to the microcontroller. As I reported before, my TC1 is of the previous design with the single voltage converter and the transformer. It would be interesting to check that on the current TC1 version's PCB. And if C7 shorts this supply, this metallization layer can well become a heating element. This means, C7 will buffer this supply line but power will flow over the metallization of the ATMEL's die. If the replacement of the apparently shorted capacitor C7 (and maybe the 5V linear voltage regulator) brought your TC1 back to life as you reported, and the microcontroller no longer heats up, the only explanation for this is that the designer of this PCB made a bad error: He may not have connected all the supply lines of the ATMEGA to Vcc individually and have the node where C7 is attached floating. Try disableing MSX display mode and experiment a little with your TIC. And that's contributing the apparent in-focus structures in your thermogram. FLIR's more recent cameras offer an optical overlay mode that they call "MSX" which is enabled by default. Moreover, there may be some active correction for this parallax error built into the thermal imager's software. The wide angle optics will result in this problem to vanish at higher distance. I assume you took the images with a FLIR ONE or a similar device which has the thermal and the optical cameras installed side-by-side, so at close distance you've got a parallax error. The thermal part of your image is too far out-of-focus to tell. But I would really like to understand the undisputable findings that in your thermal image, the microcontroller heated up while this cannot be clearly told for the capacitor. Without this optics, close-range thermographs aren't possible with this entry-level thermal I'm not questioning your repair success. Thermal camera is a "pimped" Flir E4 with an additional close-range ZnSe lens with a focal length of 75mm IIRC. If you look carefully, you see two of the tiny SMD resistors get slightly "warmish" - the high side of the zener voltage divider and the shunt of the voltage reference - and that the copper tracks below the silkscreen dissipate some of this heat. Obviously, temperature difference of this intact unit is much lower than you found on yours. But you can also see the (reflective metal) terminals that don't emit heat. You can clearly see the metal chip carrier inside the AtMega's enclosure. ![]() FYI, I attached a true in-focus close-up thermogram of my (old style) TC1 PCB after maybe three consecutive testing cycles. ![]() The thermal image itself is quite out of focus, so the sharp structures visible in there cannot be part of the thermogram. And the thermal image surely looks as if there is a visual overlay. I'm absolutely sure that in this case, it's the Atmel that's getting hot. And with "common sense", I mean, that at a maximum temperature of sixtysomething degrees, just use your finger for a quick check. But if you look at the colour grading of the heat distribution, you can clearly see the "X" shape of the chip carrier inside the Atmel. Sorry I didn't mean to sound rude or to offend you.
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