Sometimes things break in a way that it’s no longer reasonable to fix them. That’s what happened to the projector I repaired earlier. Constantly powering on and off the device and the change in temperature caused by it made the mirror rods’ gluing loosen until it collapsed. This caused the whole image projected look skewed and warped. I tried to glue it back together but it proved to be futile since in needed to be perfectly aligned, which was impossible to achieve with the tools at my disposal. The only solution to this problem would have been to order a new mirror rod from the other side of the globe, which would have been unreasonably expensive. It was time to start considering other cheaper options to view the video from my game consoles. The simplest solution seemed to be trying to find a broken flat screen television that had a functioning LCD-screen. I spent about six weeks searching until one day I went for a walk and wandered to a nearby recycling center. From there I found exactly what I had been looking for. This was the first device that I fixed that wasn’t given to me as a donation or I had found discarded in a waste disposal unit.
I bought the TV and dragged it home. After plugging the power cord into a socket I switched it on. I was a bit baffled when the TV turned on without a problem. This had to mean that somewhere inside the television there was a component that either over heated or lost its charge. My diagnosis proved to be right in just a couple of minutes as the TV powered off and began to blink one red LED-light in Morse code kind of way. At this point the story was running out of pages. The next couple of nights I spent surfing the internet and Googling while trying to deduce where the problem could lie in. Every once in a while I took my multimeter and tested spots where other people had found their TV:s to have problems. One of those spots was the current that the power board fed to the inverter for the backlight. From this point it was easier to move on. I found out that the issues on the power board were caused by a malfunction on the inverter. All the measurements I made after that pointed once again unsurprisingly to a bunch of faulty capacitors on both the power board and the inverter. With fairly small effort I found schematics of the television which helped me to determine which of the caps needed replacement. Finally I got everything done and the whole TV put back together. Plug in the power cord and power on, right? Well… No. I was disappointed and got a little mad. Sisu kicked in. Franticly clicking the power button hoping that maybe the 78th time would be the charm. It was. Or it could have been the 83rd time but never the less, it powered on. Being afraid that I just got lucky I didn’t celebrate yet. I left the TV on for a while and let it warm up before turning it off. Another try and another success. I tried this a couple more times and felt like I had reached some stability. Apparently the capacitors needed the current to rise gradually in small increments until they were at level they needed to be for proper functioning. A couple more on-off-cycles everything was running smoothly so I put the TV up for a testing period. When I initially was ready with writing the blog entry the TV had been in use for two days with no problems. All in all I spent €19,10 on the whole project of which €10 was the television itself.
This was where the story was supposed to end, but it wasn’t. After using the TV for a couple of weeks the faults started to reappear. Backlights wouldn’t light up and the red LED was blinking again. As the first measure I checked all the soldering joints I had soldered before but found nothing wrong with them. I spent a couple of days pondering the issues while staring deep into the PCB:s. I finally decided to remove the signal processing board for a check. On the underside of the board right next to a leg of a capacitor there was a small lump of solder which I assumed was a consequence of a cold solder. I re-soldered the joint and once again put the TV back together. This caused the TV to work even less than before.
A couple of weeks went by and I couldn’t come up with a solution to this issue. It was only after I brought the television to the place I interned at and testing it out with an external power supply that I got proof that the power unit of the TV was functioning as it was supposed to. I directed my attention once again to all the places I had tinkered with. My predictions were right. It wasn’t an actual defect but instead my own fault. While putting the TV back together I had accidentally pressed the pins of one connector out of place and they were causing a small shortcut. After bending the pins back I tried powering the TV on again. It turned on so I put everything back together and started using the TV. I had the TV for a year or two until it broke beyond my repairing skills so I sold it my more skilled friend who insisted on paying more than I had spent on whole project. I learnt a lot by messing around with this project. The best part was when my interning supervisor saw me staring at the circuit boards for 20 minutes and the picking up a soldering iron to re-solder that cold soldered joint he asked me if they could hire me. It was only for a couple of months but this TV made me a small profit and got me a job. I was pretty happy with this outcome.
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