I suggest you that if you want more subscribers to your channel, you should more effort into it and you should get more income from RU-vid! More details of what you are doing; specs, diagrams, what parts need to be prepared for projects ...etc. step by step, so many of hobby people follow you.....
Congratulations for showing how hard work the profession of an electronics technician is, a true technician, one of those who look for the defect piece by piece, and not a simple PCB changer. Suggestion for after the problem is solved: Apply isopropyl alcohol with a brush to the points where soldering was necessary, the marks left by the soldering iron disappear. You have gained another subscriber and a like, from those who really appreciate a job well done!
Erm, isn’t testing that stuff like that on the hot side like, deadly?!? Your fingers were touching the metal, across components etc. i was waiting for the explosion!?
We have to take your word for if there was a fault or if it was not there after you replaced the ic since you never showed or told us how to determine of a short or not. You just skim over showing and telling what you are doing too much.
The driver chip shorted, overcurrenting the fuse to failure. The capacitor being the most probable initial cause to to spikes caused by increased ripple, secondary to increasing ESR in the capacitor, lowering its efficiency and eventually, capacitive value. The ESR of the capacitor will tell the tale earliest, before complete failure or the value drifting substantially, as most cases of elevated ESR originate from the crimps that are behind the rubber seals in the electrolytic capacitor's base allowing the crimp connectors to oxidize, while electrolyte slowly evaporates, increasing the resistance in series with the capacitor.
Without those boring theories, you'd never be able to fix some SMPS units that I've repaired. Such as the primary filter cap failing, dragging the primary drive out of spec, killing some probably dodgy secondary filter caps to their demise and shorting a feedback zener and that, killing the feedback optocoupler. Once, where the zener entirely failed to faithfully short, but broke down under voltage and only detectable easily with a curve tracer. That last, generating some profanity, as my curve tracer wasn't immediately available... The boring theory part, due to the main filter on the primary gaining increasing ESR, ripple increased, causing output currents to climb, which subsequently lead to zener failure and supply runaway. Would also see in some supplies the secondary capacitors turned into popcorn, went straight into the feedback circuit, found the faults and fixed them, then went back to see if primary cap, driver or any additional secondary caps had been damaged.
Feedback: In video's thumbnail, and at 4m50s, PNP transistor is drawn upside down. Emitter (connection with arrow) should be at the Vcc side, not the GND side. R3 could be a bit larger ... presently 1k will dissipate ~150mW of energy ... a bit wasteful when there is no need for such a low value. Otherwise, schematic looks sound. 😊
Very good circuit and use of mosfet also avoided. Can I use touch plate instead of switch. By using touch plate switch may also be removed. What are the changes to use touch plate. Anil Kumar Goel
Hi bro my Samsung soundbar Q990C is not working just 1 orange Light is on. I m going to samsung service centers butt he is noy resolving this problem i m just 2 months ago buy the Samsung Q990C soundbar. Pls help me Thanks
