I thought we were testing the power supply which involves the convergence board and the deflection board. Right now the two boards are sitting outside of the TV.
They are upside down on my wooden work table so I could access the pins needed for testing.
ahh ok hook everything up. by shorting these two pins we are eliminating half of the elctrical circuitry responsible for what pushing the POWER button does.
evil said: bad transistor most likely. Have you left it shoted and looked to see if the picture works or is clear or any abnormalities?
Unfortunately I can't leave it on that long. The giant heat sink that is used for the convergence IC's came out when I took out the board. The thermal paste was flakey so I cleared off the thermal paste. Right now I have a very small amount of paste but not enough for both the IC's. Will it do damage if I leave the TV on for a minute?
are the ic's not attached to the heat sink? most are screwed or held with a metal band,how did the heat sink come off, was the solder ripped out of the board or?!?!?!
evil said: are the ic's not attached to the heat sink? most are screwed or held with a metal band,how did the heat sink come off, was the solder ripped out of the board or?!?!?!
A metal plate only pressed the IC's on the heatsink. Everthing (obviously except for the IC's) are held together by screws. The screws that hold down the heatsink also hold the convergence board to the plastic chassis so they needed to be removed so I could get the board out and do the tests.
Ok it may have to be attached to the board in order for the ic's to use it as ground to form the right waveform. you should have plenty of thermal past on the metal back of the ic's so that they have proper heat dissipation. you may have to get some more heat sink compound and order the transistor while you wait.
evil said: Ok it may have to be attached to the board in order for the ic's to use it as ground to form the right waveform. you should have plenty of thermal past on the metal back of the ic's so that they have proper heat dissipation. you may have to get some more heat sink compound and order the transistor while you wait.
I forgot to mention I had already cleaned them off. This was before I realized I had only a little compound left. I am going to an electronics store tomorrow to get a couple of hard drives for my new PC tomorrow so I'll get some paste while I am there. As far as the ground I had forgotten about that. There is a ground wire that is held on to the heatsink by the middle screw.
I am calling it a night. It is a quarter to 3 and I need some rest. I'm sure this TV is fixable now and wasn't just a waste of $100 (what I paid the previous owner to get the TV).
phew you paid a 100$ for a tv that wasnt working? You should have made them pay you to haul it off for them. im going to go back and clean up this thread a bit since its 4 pages long so others dont have to wade through the waste to get to the root of the problem. DONT FORGET to mark it as the answer.
I am able to power on the TV but I see no picture. The necks of all three tubes are glowing which means they are on. All the buttons on the front panel do not respond and the power light still doesn't light up. Is there a way to test if this transistor is still any good?
A little side question which IC on the signal board is the main processor?
I tested the transistor and it passed. This isn't the issue. I'm beginning to wonder if that disconnected wire on the signal board has something to do with it. I need to figure out where that wire goes.
I don't have a diode tester. I read I needed to test the pins for voltage coming from the emitter and the collector (I believe) flowing only in one direction which is what I got.
The only measuring tool I have is a multimeter capable of measuring only voltage and resistance.
Take it to a repair shop with better tools and let them look at it. They probably wouldn't charge you much, and they probably could order you a replacement.
evil said: Take it to a repair shop with better tools and let them look at it. They probably wouldn't charge you much, and they probably could order you a replacement.
They want to charge me $100 just to look at it. I'm not paying that much. I was given a tip to try turning it on with a remote as these WS model TV's have been known for bad front panel switches. I was told to check for 5 volts on the infrared sensor and if the 5 volts were there then to try turning on the TV with a remote. This could be due to the front panel lock activation or possibly a bad front panel circuit board. Since I found there are 5 volts on the sensor I will try to turn on the TV when I get home. I will come back later with results once I get my Comcast remote (I don't have the original remote)
100$ to test a transistor is wrong maybe you should try to find a different repair shop or try repairing what's broken.... I don't know anyone who doesn't use a remote to turn a tv on, I would have thought that would be the second thing you would have tried. Even so I bet the people who had the tv before you had a remote for it and I just don't see them throwing it away because they couldn't turn it on with the button on the front of the tv.... If all else fails hard wire the base and emiter pin to a switch.
I still get no response from the TV after using a remote. I will continue to call around shops. I hard wired the power switch not long after I brought the TV home and it did nothing. I think the disconnected wire I mentioned has something to do with the issue. I just don't know where it goes. Do you know where I can get the signal board # 930B868 (or a very clear picture of it)? I need to have a direct comparison to look at so I can see where the wire goes.
I didn't use a remote to try turning the TV on at first because I don't have a remote for it.
They are upside down on my wooden work table so I could access the pins needed for testing.
ahh ok hook everything up. by shorting these two pins we are eliminating half of the elctrical circuitry responsible for what pushing the POWER button does.
Everything is hooked back up. I know what I am supposed to short out. What will I be keeping a lookout for?
After a few startles of suddenly hearing a relay click I left it shorted just long enough to hear the tubes fire up.
awsome, im having some connectivity issue with my email carrier so I may not know immediately when you write back.
Have we got a diagnosis?
bad transistor most likely. Have you left it shorted and looked to see if the picture works or is clear or any abnormalities?
Unfortunately I can't leave it on that long. The giant heat sink that is used for the convergence IC's came out when I took out the board. The thermal paste was flakey so I cleared off the thermal paste. Right now I have a very small amount of paste but not enough for both the IC's. Will it do damage if I leave the TV on for a minute?
are the ic's not attached to the heat sink? most are screwed or held with a metal band,how did the heat sink come off, was the solder ripped out of the board or?!?!?!
A metal plate only pressed the IC's on the heatsink. Everthing (obviously except for the IC's) are held together by screws. The screws that hold down the heatsink also hold the convergence board to the plastic chassis so they needed to be removed so I could get the board out and do the tests.
Ok it may have to be attached to the board in order for the ic's to use it as ground to form the right waveform. you should have plenty of thermal past on the metal back of the ic's so that they have proper heat dissipation. you may have to get some more heat sink compound and order the transistor while you wait.
I forgot to mention I had already cleaned them off. This was before I realized I had only a little compound left. I am going to an electronics store tomorrow to get a couple of hard drives for my new PC tomorrow so I'll get some paste while I am there. As far as the ground I had forgotten about that. There is a ground wire that is held on to the heatsink by the middle screw.
I am calling it a night. It is a quarter to 3 and I need some rest. I'm sure this TV is fixable now and wasn't just a waste of $100 (what I paid the previous owner to get the TV).
phew you paid a 100$ for a tv that wasnt working? You should have made them pay you to haul it off for them. im going to go back and clean up this thread a bit since its 4 pages long so others dont have to wade through the waste to get to the root of the problem. DONT FORGET to mark it as the answer.
I am able to power on the TV but I see no picture. The necks of all three tubes are glowing which means they are on. All the buttons on the front panel do not respond and the power light still doesn't light up. Is there a way to test if this transistor is still any good?
A little side question which IC on the signal board is the main processor?
It's an npn google, testing an npn transistor
I tested the transistor and it passed. This isn't the issue. I'm beginning to wonder if that disconnected wire on the signal board has something to do with it. I need to figure out where that wire goes.
I don't have a diode tester. I read I needed to test the pins for voltage coming from the emitter and the collector (I believe) flowing only in one direction which is what I got.
The only measuring tool I have is a multimeter capable of measuring only voltage and resistance.
Take it to a repair shop with better tools and let them look at it. They probably wouldn't charge you much, and they probably could order you a replacement.
They want to charge me $100 just to look at it. I'm not paying that much. I was given a tip to try turning it on with a remote as these WS model TV's have been known for bad front panel switches. I was told to check for 5 volts on the infrared sensor and if the 5 volts were there then to try turning on the TV with a remote. This could be due to the front panel lock activation or possibly a bad front panel circuit board. Since I found there are 5 volts on the sensor I will try to turn on the TV when I get home. I will come back later with results once I get my Comcast remote (I don't have the original remote)
100$ to test a transistor is wrong maybe you should try to find a different repair shop or try repairing what's broken.... I don't know anyone who doesn't use a remote to turn a tv on, I would have thought that would be the second thing you would have tried. Even so I bet the people who had the tv before you had a remote for it and I just don't see them throwing it away because they couldn't turn it on with the button on the front of the tv.... If all else fails hard wire the base and emiter pin to a switch.
I still get no response from the TV after using a remote. I will continue to call around shops. I hard wired the power switch not long after I brought the TV home and it did nothing. I think the disconnected wire I mentioned has something to do with the issue. I just don't know where it goes. Do you know where I can get the signal board # 930B868 (or a very clear picture of it)? I need to have a direct comparison to look at so I can see where the wire goes.
I didn't use a remote to try turning the TV on at first because I don't have a remote for it.
Imagine that.... I never said anything about hard wiring the power button!?! If you want to keep chasing your tail with an unused wire try google.
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