Recently a friend gave me a Philips 19PFL3403D/27 flat panel TV. They said the TV worked but the image was "fuzzy." They were so fed up with the TV that even if I fixed it they didn't want it back. Hey, free TV for me, that works.
I'm not exactly sure what a "fuzzy" image is, especially with an LCD TV. My thought was maybe a problem in the ATSC tuner, or maybe a back light issue and my friend did a very poor job of describing the issue. First thing I did was plug it in and turn it on. The TV appeared to work fine. I did notice some occasional popping noise from the speakers, but that could have been from the signal (I was using a cheap set of rabbit ears to pick up local TV). I decided to go the extra mile and open the back and have a look. This TV opens like most TVs of the same size. A few screws at the bottom and then plastic tabs around the edge. Once open the TV has the standard layout, power and invert board on the left and video input and processing on the right. Sorry I didn't snap any pictures, I didn't have my camera with me.
With the back off the TV I noticed several things. First, there was a noticeable high-pitched whine coming from the power/inverter board. Second, every cap in the TV was CapXon, known crappy caps. Even though I have an ESR meter and every cap tested fine, I decided to recap the TV. After all, it's only a matter of time until they go bad. The power/inverter board had relatively few caps, but the video board had about 40. I'm not going to list all the caps here for reasons that will become evident later on.
Once my digikey order arrived I first recapped the power/inverter board. This actually went very smoothly. These were some of the easiest caps to remove. After that the high-pitched whine was barely audible. You could still hear it with you ear right next to the board.
Then I moved onto the video board. Well for how easy the power/inverter board was, the video board was the most difficult board I've ever worked on. I had to use every trick I'm aware of to get these caps out. First I had to melt in leaded solder to lower the melting point. Did that several times per joint. I then used a solder sucker, followed by solder wick. But that still wasn't enough, I had to heat up one joint and slowly walk the capacitor out. And even then once it was removed, I often times had holes plugged with solder which I needed to use more wick on. It was taking me about 5 minutes per cap, and there were about 40 caps. Needless to say in the end I replaced about 1/3 of the caps before I decided I'm more likely to over heat or damage the board and so I stopped.
The reason why soldering on this board was so difficult is clear - the back side of the board is one huge copper ground plain. To make matters worse, the top side of the board has fat copper traces as well. So no matter what component you try and remove, there is a ton of copper to heat up. I have a high-end Hakko soldering station, so the difficulty is not because of bad equipment.
After putting it back together the TV still works, but then it worked before hand. So I don't know that anything was wrong, I think I just wasted a lot of my time and about $15 in caps. If anyone else needs to work on this TV, I would only suggest working on this TV if 1) the problem is on the power/inverter board, 2) you're looking to replace a small number of known bad caps or 3) you have a desoldering gun - and even if you have a desoldering gun, I'm guessing you're still going to have a hard time. So consider yourself warned, work on the video board at your own risk.
The worst part about this is it turns out this is a crappy TV in my opinion. The manual clearly states the TV is a 16:9 aspect ratio, but the screen is exactly 16" by 10". Hmm, you don't have to be good at math to tell that's a 16:10 aspect ratio. The TV automatically stretches 16:9 broadcasts to fit this 16:10 screen, so it's clear all images are distorted vertically. The manual also claims the native resolution is 1440x900. However, I connected my laptop via HDMI to the TV. I don't know what the actual native resolution of this TV is, but it's not 1440x900. It's definitely some very obscure resolution because my laptop didn't support the native resolution.
So in short, this TV is kind of a piece of junk - it's poorly spec'ed and uses cheap components. It was free to me and I'll find something to do with it, but I'm beginning to understand the previous owners frustration.
I'm not exactly sure what a "fuzzy" image is, especially with an LCD TV. My thought was maybe a problem in the ATSC tuner, or maybe a back light issue and my friend did a very poor job of describing the issue. First thing I did was plug it in and turn it on. The TV appeared to work fine. I did notice some occasional popping noise from the speakers, but that could have been from the signal (I was using a cheap set of rabbit ears to pick up local TV). I decided to go the extra mile and open the back and have a look. This TV opens like most TVs of the same size. A few screws at the bottom and then plastic tabs around the edge. Once open the TV has the standard layout, power and invert board on the left and video input and processing on the right. Sorry I didn't snap any pictures, I didn't have my camera with me.
With the back off the TV I noticed several things. First, there was a noticeable high-pitched whine coming from the power/inverter board. Second, every cap in the TV was CapXon, known crappy caps. Even though I have an ESR meter and every cap tested fine, I decided to recap the TV. After all, it's only a matter of time until they go bad. The power/inverter board had relatively few caps, but the video board had about 40. I'm not going to list all the caps here for reasons that will become evident later on.
Once my digikey order arrived I first recapped the power/inverter board. This actually went very smoothly. These were some of the easiest caps to remove. After that the high-pitched whine was barely audible. You could still hear it with you ear right next to the board.
Then I moved onto the video board. Well for how easy the power/inverter board was, the video board was the most difficult board I've ever worked on. I had to use every trick I'm aware of to get these caps out. First I had to melt in leaded solder to lower the melting point. Did that several times per joint. I then used a solder sucker, followed by solder wick. But that still wasn't enough, I had to heat up one joint and slowly walk the capacitor out. And even then once it was removed, I often times had holes plugged with solder which I needed to use more wick on. It was taking me about 5 minutes per cap, and there were about 40 caps. Needless to say in the end I replaced about 1/3 of the caps before I decided I'm more likely to over heat or damage the board and so I stopped.
The reason why soldering on this board was so difficult is clear - the back side of the board is one huge copper ground plain. To make matters worse, the top side of the board has fat copper traces as well. So no matter what component you try and remove, there is a ton of copper to heat up. I have a high-end Hakko soldering station, so the difficulty is not because of bad equipment.
After putting it back together the TV still works, but then it worked before hand. So I don't know that anything was wrong, I think I just wasted a lot of my time and about $15 in caps. If anyone else needs to work on this TV, I would only suggest working on this TV if 1) the problem is on the power/inverter board, 2) you're looking to replace a small number of known bad caps or 3) you have a desoldering gun - and even if you have a desoldering gun, I'm guessing you're still going to have a hard time. So consider yourself warned, work on the video board at your own risk.
The worst part about this is it turns out this is a crappy TV in my opinion. The manual clearly states the TV is a 16:9 aspect ratio, but the screen is exactly 16" by 10". Hmm, you don't have to be good at math to tell that's a 16:10 aspect ratio. The TV automatically stretches 16:9 broadcasts to fit this 16:10 screen, so it's clear all images are distorted vertically. The manual also claims the native resolution is 1440x900. However, I connected my laptop via HDMI to the TV. I don't know what the actual native resolution of this TV is, but it's not 1440x900. It's definitely some very obscure resolution because my laptop didn't support the native resolution.
So in short, this TV is kind of a piece of junk - it's poorly spec'ed and uses cheap components. It was free to me and I'll find something to do with it, but I'm beginning to understand the previous owners frustration.