Saturday, February 1, 2014

Will disassemble for food

All my life I have disassembled things. There are three scenarios that can happen when you crack things open. The first is you can take something apart knowing well in advance you won't be able to put it back together correctly again ever. This gives you some freedom to really explore, even if you need a hammer. The second is opening something up and you can put it back together again, ahem correctly.

The third is when you believe you should have been able to reassemble the whatever, and then something unexpected happens. This could be a critical spring loaded part that rapidly travels away from you at the speed of light never to be seen again, or some delicate thingamabob you inadvertently broke while trying to remove it.


I'm always curious about how things work, and how they're made. It's made me a better tech, and generally fearless in most cases because majority of the stuff I eviscerate is nonoperational in the first place. This gives you some confidence right out of the box.

What you're looking at is the inside of a Garmin chart plotter. I can't remember for sure but I think it's a 2010C. I wasn't expecting magic on the inside, but the case was surprisingly empty. I could have stowed my lunch in the extra space. It looks like the case was originally designed for a second board, or possibly a larger one.

You can see the two ribbon cables for the soft keys at the bottom, and the side mounted keys. Another larger ribbon cable feeds the display, and I think the two brown looking straps are for moving recalcitrant stray electrons to a new home, or possibly providing power to the display.

If redesigned today this would be a far more compact package. I opened it up on the off chance there would be an obvious problem, but there was nothing burned, or busted that I could see. There was some staining inside the case that indicated some sort of liquid had been present at some time in the past. I have been lucky on many occasions, but this time not so much.

Today however is different. I'm going to assist in exploratory surgery on a working 60" plasma TV. It's going to be exciting. I've always wanted to know what's inside one and now's my chance.

This is my good friend Dan's TV. It has developed an annoying habit. Even though the sound is being fed to an external sound system, the TV's volume for some unknown reason automatically turns itself down. 

Since he's using a audio pre-amp output from a cable box you don't actually hear the volume drop. The real issue is the TV leaves an annoying icon on the screen after the un-commanded volume turn down. It's the TV's way of telling you the sound is now off. I don't know what the software people were thinking, but it wasn't necessary to do this in the first place. Humans have these things called ears. They can tell if the sound is on or off.

Dan did some Google searches and discovered this wasn't an unknown problem with this genre of TV, and the fix seems at first blush easy. Armed with my tool bag I show up, and everything is prepped. The TV weighs a lot, and it takes the two of us with a lot of grunting noises to get the beast free and lugged onto the operating table.

It was easier than I thought it would be to remove the back. The gas passer put the TV to sleep, and the  screwdriver was sterilized.  There were no hidden fasteners, weird clips, or funky hinges like you find on many major appliances. Remove screws, lift the cover off, and there were the exposed digital entrails. Look away now if you're prone to being squeamish.

It's an amazing piece of engineering and fabrication all packed in a case that's about two inches thick. Substantial power supply, a logic board running the show, speakers and a zillion tiny florescent tubes, one for each individually addressed pixel. 

So here is the theory. The problem is alluded to occur with a volume button problem on the manual operation keypad. So the fix is purported to be disconnecting it from the system. You can still use the remote control, which is what is used anyway.  All we have to do is to locate the board, and simply pull the offending plug out.

Keen eyes spot it hidden under what we think was a odd looking rectangular speaker. Two screws come out, and the device gets gently moved to the side. As advertised there's the board we're looking for. Hemostats pull the wee plug out, job done. The speaker goes back into place. The back is put back on, more groaning noises commence in hanging the TV. Dan's wife Carla has to help us guide the set onto the mount because we can't see it with any grace, and cables are reattached. Dan grabs the remote and sound comes on, but no picture. Just a blank screen mocking us.

Hmmm, are the cables correctly attached? We have power, I saw the blue light flash when it was plugged in. Doing what professionals are apt to do, the remote buttons are all pushed a bunch of times, along with another remote's buttons.

Maybe the batteries are low, let's get close to the set and try them again. No joy, black screen, a sinking feeling, and with a collective sigh the process is reversed. It seems the plug and little board were doing some important things, among which was allowing the TV set to turn on.

Lying again face down again on the operating table the surgery is reversed. After repeating the re-reinstallation gyrations for a second time, Dan again nervously presses the remote, and the TV turns on. It's the Christmas miracle, a successful Mars landing, seas parted, and a choir of angels are singing. By this I mean at the very minimum our ministrations hadn't permanently destroyed a very large and expensive TV. I was most relieved. Also the annoying icon problem now appears to be fixed.

To be honest, in the end, we don't really know for sure what fixed it. Maybe unplugging the board or TV reset some software inside it, or playing with the menus cleared some feature. In the end however, sometimes it's just better to be lucky than smart.

So fear not. If it's busted crack it open and see what makes it tick. You may learn something in the process. My attorneys have advised me some objects may include dangerous electrical currents, chemicals, radiation, and sharp or moving parts. Safety glasses should be used if you're using a hammer to open a stubborn device. Doing this to operating equipment will void your warranty, and please count your fingers afterwards. Personally I find thumbs are big help when using tools.

3 comments:

  1. Loved it, Bill. Thanks for your electronic expertise!

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  2. When you opened the case the first time, the bug got pissed! When you opened the case the second time the bug took off!

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  3. Point-point wiring may have been a service nightmare but on the other hand, way fewer connectors.

    Bill tried to be subtle here with "we'll leave it disconnected" diversion gambit but he blew the secret: what laypersons think are "magic healing hands" backed by by supernatural intelligence are only mortal paws following the standard prescription that cures so many ills: disconnect, reconnect and voila...

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