Tony Stewart when it is replaced it work for four to five days only. Afterward it burnt with smoke, display disappear and cannot start.
If the resistor is stopping it working, then it's NOT where you showed it on the rough circuit - as that's only a safety component and has no effect on it working.
Tony Stewart when it is replaced it work for four to five days only. Afterward it burnt with smoke, display disappear and cannot start.
Here I tried and reconstruct the damage circuit
Nigel Goodwin when it start burning sound got distorted, displaying white lines and colors become black and white like tv without signals. As you said above I need service manual and its components data which i have been looking for so long but cannot find till date. If cannot find I'll try with high value range(4.7M to 10M, with capacitors varying from 1nF to 4.7nF) suggested by you. Let me return to this page. Thank you Nigel Goodwin
The service manual is available from here https://www.electronica-pt.com/esquema/func-startdown/14805/
but it does not contain the schematic of the power supply.
It does say that the leakage to earth from the chassis should be less than 0.5 mA. (So the resistor that is burning out should be at least 500 K assuming 240 volt mains.) If the component CY101 which connects to the other leg of the mains (See picture in post #23) was short circuit or leaky it could explain why the resistor is burning out. (I think CY101 and CY102 could be spark gaps.)
As others have said this failure should not stop the item from working. There must be another fault somewhere. The fact that this resistor is burning out is potentially dangerous as the antenna connector may be connected to the chassis. (It could also be isolated from the chassis with capacitors.) Due to the potential danger from the fault I think the OP should either get someone with more knowledge to look at the fault or replace the power supply board.
If the resistor is burning up, that can mean several things.
1. The unit is drawing more current than it should for some reason, such as aging CCFL tubes which usually trigger shutdown of HVDC supply.
2. The resistor is too large a value and is overheating.
3. The resistor was replaced with an undersized for the nominal current and I^2R = Pd .
Considering there is no power between Neutral and ground and maybe 0.5mA, a schematic error is the only thing that makes sense as suggested in #22
Pls explain how this burns up a resistor unless Line and Neutral are reversed,
The service manual is available from here https://www.electronica-pt.com/esquema/func-startdown/14805/
but it does not contain the schematic of the power supply. It does say that the leakage to earth from the chassis should be less than 0.5 mA. (So the resistor that is burning out should be at least 500 K assuming 240 volt mains.) If the component CY101 which connects to the other leg of the mains (See picture in post #23) was short circuit or leaky it could explain why the resistor is burning out. (I think CY101 and CY102 could be spark gaps.) As others have said this failure should not stop the item from working. There must be another fault somewhere. The fact that this resistor is burning out is potentially dangerous as the antenna connector may be connected to the chassis. (It could also be isolated from the chassis with capacitors.) Due to the potential danger from the fault I think the OP should either get someone with more knowledge to look at the fault or replace the power supply board.
Les.
Thanks Les Jones for the service manual and your help. Now I can have the right value. Yes the main AC line volt is 133v and there is dangerous current with the antenaThe service manual is available from here https://www.electronica-pt.com/esquema/func-startdown/14805/
but it does not contain the schematic of the power supply. It does say that the leakage to earth from the chassis should be less than 0.5 mA. (So the resistor that is burning out should be at least 500 K assuming 240 volt mains.) If the component CY101 which connects to the other leg of the mains (See picture in post #23) was short circuit or leaky it could explain why the resistor is burning out. (I think CY101 and CY102 could be spark gaps.) As others have said this failure should not stop the item from working. There must be another fault somewhere. The fact that this resistor is burning out is potentially dangerous as the antenna connector may be connected to the chassis. (It could also be isolated from the chassis with capacitors.) Due to the potential danger from the fault I think the OP should either get someone with more knowledge to look at the fault or replace the power supply board.
Les.
This LCD tv is 4yrs old and its aging ccfl may be the cause. This reristor had blown thrice and I used to replace with 47ohms as suggested by local tech. Thanks for your informative help. I'll turn down and seeIf the resistor is burning up, that can mean several things.
1. The unit is drawing more current than it should for some reason, such as aging CCFL tubes which usually trigger shutdown of HVDC supply.
2. The resistor is too large a value and is overheating.
3. The resistor was replaced with an undersized for the nominal current and I^2R = Pd .
A PTC can be added in contact with the power resistor so that it can prevent over current and shutdown safely without burning out any parts, but will shutdown until cooled but the problem may be 1 above , so CCFL's need to be replaced with same.. Clues to aging are warm white in the corners or ends of the CCFL tubes.
Turn down the brightness may help.
**broken link removed**
This LCD tv is 4yrs old and its aging ccfl may be the cause. This reristor had blown thrice and I used to replace with 47ohms as suggested by local tech. Thanks for your informative help. I'll turn down and see
Nigel Goodwin according to your suggestion i fixed up without the resistor and the blue component, its working fine without any problem! but there is strong current with the antenna. should i replace with 500k ohm resistor?None of what he posted was in any way relevant, as he was still assuming it was a surge limiter resistor - for that matter, ageing CCFL tubes wouldn't cause any such effect either.
Not according to UL requirements. it is 3.5mA at 60Hz leakage to ground MAX per stationary unit.Well you can usually draw considerably more between earth and neutral than 0.5mA, but it's only a small voltage.
They curbed using 2 pin plugs since VGA ports were added to TV's and monitors to reduce emissions.That wouldn't do it either, live and neutral are unlikely to be fixed, particularly in the USA with two pin plugs.
It wasn't clear if the unit stopped working or it just started to fizzle. Nor was it clear what R values were originally there and replaced with same value and power rating and if in close proximity to a PTC which will regulate at 85'C during protection.Nor would totally removing the resistor and Y2 capacitor stop the unit working, as they are just safety components - to prevent static build-up.
As I indicated as CCFL's age they draw more power which would only affect series power drop Resistors.Presumably there's a fault elsewhere?, and someone has somehow bodged things so badly that it's somehow passing current through this resistor, and they changed it for a massively lower value for that reason.
But I'm pretty bemused as to what you could do to cause that, and how someone could do something so badly wrong?.
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