In the ongoing series entitled, Sometimes You Surprise Yourself – a few weeks ago I successfully repaired my big screen television.
In our last episode, I repaired my laptop by baking the motherboard in my oven. In this episode I explain how it may be possible, depending on which television you have and what the problem is, to repair it yourself with $35 in tools, a $75 repair kit and complete ignorance of how to repair anything electronic.
So the cableman came to my house a few weeks ago to install Cox’s new Whole Home DVR. After he installed the new box and turned the TV on, the picture was split into three mirror images, each image was either red, green or blue and it was bending at the top of the screen. It looked very much like those old 3D style movies when you take the 3D glasses off. In a word, unviewable. In another word, bricked. Ironically, it had been working fine the night before the cable guy touched it - I’m just sayin’….I’m j-u-s-t sayin’.
Google, the all-knowing Oracle, told me that my convergence chips had most likely blown and would need to be replaced. The convergence chips, as you can imagine, converge the three primary colors of the spectrum into the image you normally see on the screen, mixing the colors in exactly the right proportions to make all the other colors your eye can see. It would appear these are one of the first things to go and very commonly fail.
This TV is about 9 years old and is one of those projection TV’s that marked the transition between the very large box-type big screens and the new incoming flat screens. The new flat screens were ridiculously expensive, as is common with new technology, even a small 35″ TV was a few thousand dollars. Everyone saw the inevitable though; that big box TV’s would be replaced by these new market entrants. As the price of flat screens slowly came down over the months, they crushed the price of big box TV’s down under them. Stores wanted to clear them out and make room for the newcomer so their prices were dropping monthly. I saw an opportunity in this market transition so I was able to buy a 65″ SONY rear-projection HDTV (720p) for just under $2,000 (including the $100 I asked them to knock off for some scratches on the plastic frame of the floor model). At the time HD was still relatively new and there were very few HD channels.
So when the cableman broke my TV, or not, I decided to look at replacement costs. A 65″ Sony flat screen is $3,000 at Best Buy. I had decided a few years ago that if this TV let go, and assuming I had a house at the time, which I do now, I was going to replace it with an overhead projection system anyway which would be at least as much as a replacement TV.
I decided to ask the Google Oracle again, what other options I might have.
That is when I found a website that offers convergence chip repair kits for many types of rear-projection TV’s for $75 each. I typed in the model number from the back of my TV and up popped the kit number I needed. I put in my credit card information and a week later the package arrived.
In the package was a small document that told me what I would have to do with the parts. In order to make this repair, I would need to desolder the old chips out and solder the new chips in as well as check continuity on a dozen or so little resistors. Let me add that I have never soldered anything in my life. My Dad is very good at it, and I’ve seen him do it, but that’s as far as my knowledge goes.
The document had an internet address on the vendor’s website that served as an instructional page on how to solder and desolder, including graphics on what a good and bad solder connection looks like. What I really liked about this company was the detail they went to in order to walk anyone, even if you have never touched a circuit board before (like me, outside of the one in the oven). The detail was so exact that they even had a graphic that showed where each screw should be on the board in the TV so I could remove it – and that graphic was needed because there were two screws I would never have seen had the graphic not told me where to really focus my attention.
I already had an old analog continuity meter that I had never used, they are very cheap – maybe $20 or less. The soldering pen, the desoldering iron, and the solder can all be bought at Radio Shack. The instructions advised that I also pick up a small circuit board and some DIP switches so I can practice soldering by soldering the DIP switches into the circuit board. Total Radio Shack bill was about $35.
I spent about an hour practicing how to solder and desolder with the DIP switches and the practice circuit board. Then I pulled up a weblink the package instructions provided that took me to their website that had very detailed steps, with photos, for my exact model TV on how to get inside the back of the TV, remove all the cables, bridge connectors and screws so I could remove the board that contained the convergence chips.
Once I had the board out, I checked all the resistors with the meter. All but one was fine. I desoldered that one and replaced it with one from the kit. Then I desoldered the convergence chips and replaced them with the new ones. My soldering job was not great, and I had to desolder some mistakes and redo them which was no simple task since each of the two covergence chips had a dozen pins or so and each one needed to be soldered to the board and the board cannot be removed from the TV, only turned slightly to work on, so it’s not a comfortable position.
I was so concerned about my soldering job that once I had the board back in place, all the wires re-attached and the bridges connected I went upstairs and grabbed both fire extinguishers from under the kitchen sink, my vapor mask and my safety goggles. I also gave my wife the walkie-talkie (she was on the other side of the house with the baby) and put her cellphone near her so if I radioed in that the bottom floor was on fire she could call the fire department while I emptied the fire extinguishers and ran outside in flames for the garden hose.
Anticipating a snap, crackle and pop, I plugged in the TV. Nothin’. Holding the extinguisher at the ready in one hand with the remote control in the other…my goggles fogging up around the corners as they fit snuggly over my eyes and breathing like Darth Vader through my vapor mask, I turned on the remote. Crackling…lights…picture…
Mission Control, we have convergence!
So what have we learned? That my dog only cares about tanning.
Categories: Personal Message