Remote control pm my Toshiba TV
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Jack Riblet
- Posts: 5
- Joined: Tue Jul 12, 2005 1:01 am
- Location: Wadesboro, NC
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Remote control pm my Toshiba TV
The remote control feature on my TV quit a year or so ago. I had a TV Serviceman in to check it out. He couln't find any thing wrong with the circuit board. No cracks or anything. I left it go for a while and quite by accident I hit one of the volume buttons and it worked. The on/off button also worked but after a short time, it quit again. Again after a long period of time I found the remote features working again. This time it lasted for almost 2 days before it quit. The last time, just a couple days ago, I hit one of the feature buttons and it worked but only for a few minutes before it failed again. Anyone have any ideas?
I have a Kenwood stereo tuner that has been giving me trouble for a while. I discovered that the problem is temperature related....I keep the place kinda cool....if I warm it up it starts working again...my theory is that the conductive pads on the back side of the rubberized keyboard become unconductive at cooler temps.... If any one has a counter theory.... I'm interested.
With any troubleshooting, you have to determine whick is the culprit. Can you eliminate the remote control by using a universal remote? If the remote control is the problem the solution is simple and not worth trying to fix as universal remotes cost pennies. If the problem is on the receiver side that is another issue but you have to rule out one or another.
Try viewing the infrared through a video camera or digital camera and see if the remote is always sending out light pulses.
Try viewing the infrared through a video camera or digital camera and see if the remote is always sending out light pulses.
"Who is John Galt?"
Jack: Since the remote reciever in the TV seems to respond to mechanical input, this strongly suggests a mechanical interconnect fault such as a cold solder joint. Simply try reflowing a bunch of the most susceptable joints. These would be associated with any connectors, headers or support posts or larger components like the switches themselves. A careful probing while the set is powered might even localize the exact spot. Sounds hopeful.
Cato, Some remotes have crystal oscilators to set the carrier frequency. A very out of spec crystal might shift its frequency enough with temp to make it work or not. Conversely you may be right about the buttons but try cleaning the contact surface, it may be a contaminant that is temp sensitive rather than the material itself. I would think the #1 contaminant in remote controls is soda pop.
Or are you speaking of the tuner itself? In that case it could also be a cold solder joint responding to mechanical input via heating of the PCB and interconnects. If you had a schematic, you would be able to narrow it down quite a bit and use signal tracing to find the defect.
Cato, Some remotes have crystal oscilators to set the carrier frequency. A very out of spec crystal might shift its frequency enough with temp to make it work or not. Conversely you may be right about the buttons but try cleaning the contact surface, it may be a contaminant that is temp sensitive rather than the material itself. I would think the #1 contaminant in remote controls is soda pop.
Or are you speaking of the tuner itself? In that case it could also be a cold solder joint responding to mechanical input via heating of the PCB and interconnects. If you had a schematic, you would be able to narrow it down quite a bit and use signal tracing to find the defect.
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Jack Riblet
- Posts: 5
- Joined: Tue Jul 12, 2005 1:01 am
- Location: Wadesboro, NC
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Remote Problem
I have 3 remote devices. One came with the TV the other two are the universial types. When one works or doesn't work, they all respond that way. I'm sure the problem isn't with the remotes. The TV Serviceman looked over the circuit board(it's a seperate section behind the infrared sensor) with a eye piece, looking for any cracks or breaks. Not sure what you mean by mechanical input except that yes I can turn the TV on/off with the button on the front, or change the volume level. Many of the features on the TV ( type of sound, color or tine of picture, those kind of things)can only be done using a remote. This problem has happened during the summer and winter so I don't think temp is a cause. I have a Sat system and all the remotes work fine when I use them to power up or change channels, it's only the TV features (on/off, volume, mute and so forth) that are the problem.
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Robert Reed
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Well Jack
I hate to tell you this story, but I had a similar problem with my set. A quick 'scope check at the set's IR detector out put showed the IR signal was definately passing through. From that point , the data was directly inputted to a VLSI chip (68 pins). The chip performed many internal TV functions, remote operation being one of them . All functions were operational except for remote data input. Because of that one defective input, I had to replace the chip ($55 and a half days work). It broke my heart. Have you examined the IR receievers output? Its fairly easy to do.
I hate to tell you this story, but I had a similar problem with my set. A quick 'scope check at the set's IR detector out put showed the IR signal was definately passing through. From that point , the data was directly inputted to a VLSI chip (68 pins). The chip performed many internal TV functions, remote operation being one of them . All functions were operational except for remote data input. Because of that one defective input, I had to replace the chip ($55 and a half days work). It broke my heart. Have you examined the IR receievers output? Its fairly easy to do.
Jack,
By mechanical input I mean that you can "mechanically" push or otherwise physically move the electronic assemblies to cause them to function and malfunction.
I said that because it seemed like the remote started working for a while after pushing buttons on the TV. These buttons could transmit mechanical force from the PCB they are mounted on to an adjascent connector or header where the cold solder joint might be.
Your more recent explanation brings to mind a similar situation I had.
I too have several remotes for a particular TV, one day they all seemed to stop working intermittantly. There seemed to be no pattern to when it would work at first until I examined the one of the remotes. Seems a button had stuck down and it was transmitting continuously to the TV. While this one remote was being recognized by the reciever, all other remotes were ignored except when I unknowingly blocked the beam from the first.
Its unlikely you have the same problem but the test is trivial. Remove the batteries from all remotes except the one you are testing or put them in a drawer. Its unlikely because it would only last as long as the batteries held out.
I use a little phosphor coated card I got from radio shack. Just point the remote at the card and it will glow red where the IR light hits it. Very simple, very cheap. Cat# 276-1099 (on mine) if they still make them
This is the same principal behind remote control wars where you try to get it to stay on your channel while someone with another tries to change it to theirs, you just hold a button (like status) to lock your opponent out after selecting your channel.
By mechanical input I mean that you can "mechanically" push or otherwise physically move the electronic assemblies to cause them to function and malfunction.
I said that because it seemed like the remote started working for a while after pushing buttons on the TV. These buttons could transmit mechanical force from the PCB they are mounted on to an adjascent connector or header where the cold solder joint might be.
Your more recent explanation brings to mind a similar situation I had.
I too have several remotes for a particular TV, one day they all seemed to stop working intermittantly. There seemed to be no pattern to when it would work at first until I examined the one of the remotes. Seems a button had stuck down and it was transmitting continuously to the TV. While this one remote was being recognized by the reciever, all other remotes were ignored except when I unknowingly blocked the beam from the first.
Its unlikely you have the same problem but the test is trivial. Remove the batteries from all remotes except the one you are testing or put them in a drawer. Its unlikely because it would only last as long as the batteries held out.
I use a little phosphor coated card I got from radio shack. Just point the remote at the card and it will glow red where the IR light hits it. Very simple, very cheap. Cat# 276-1099 (on mine) if they still make them
This is the same principal behind remote control wars where you try to get it to stay on your channel while someone with another tries to change it to theirs, you just hold a button (like status) to lock your opponent out after selecting your channel.
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Jack Riblet
- Posts: 5
- Joined: Tue Jul 12, 2005 1:01 am
- Location: Wadesboro, NC
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It's not the remotes. I can't believe they would all quit at the same thime and then start working again at the same time. It's in the TV circuit somewhere. I contacted Toshiba Customer service and explained the problem. They told me to take it to a athorized dealer. Some customer service that is. Can anyone out there tell me how and where I can get me a new remote circuit board. Toshiba customer service again was no help. They showed a list of electronics dealers that may or may not be able to get me the part I need. All of which I have to make long distance calls too. Brother that the last time I buy anything Toshiba.
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