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Panasonic TV EVO 51 chassis TNP4G073. Lightning damage to HOT. Replaced regulator and HOT Transistor. Tested all other parts in HOT circuit all tested fine. Volts at collector of HOT Transistor is between 27.5 V and 28.5 V. Power led flickers on and off rapidly. LOPT tested on another board and it is fine. Could you please suggest what else could be wrong.

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Try ic801 SE090 regulator on secondary of power-suply

Posted on Apr 20, 2011

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Panasonic tv model evo 51 no switching on but beeps on standby, switched off using remote control, now no on but long beep sound


Fault to the main power supply regulator section. Either it will be on a separate board, or on the part of its main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electronicshelponline.blogspot.com/
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.

Sep 19, 2015 | Panasonic Televison & Video

1 Answer

No power just went out.....


Hello,

  • A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!
    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement (including slo-blow if that is what was there originally). Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem (e.g., if the new fuse is not slo-blow and is blown by the degauss circuit inrush current but nothing is actually wrong).
    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:
    • Degauss Posistor - very likely.
    • Horizontal output transistor.
    • Power supply regulator if there is one.
    • Power supply chopper (switchmode) transistor if there is one.
    • Diode(s) in main bridge
    • Main filter capacitor(s).
    You should be able to eliminate these one by one.
    Unplug the degauss coil as this will show up as a low resistance.
    First, measure across the input to the main power rectifiers - it should not be that low. A reading of only a few ohms may mean a shorted rectifier or two or a shorted Posistor.
  • Test the rectifiers individually or remove and retest the resistance.
  • Some sets use a Posistor for degauss control. This is a little cubical (about 1/2" x 3/4" x 1") component with 3 legs. It includes a line operated heater disk (which often shorts out) and a PTC thermister to control current to the degauss coil. Remove the posistor and try power. If the monitor now works, obtain a replacement but in the meantime you just won't have the automatic degauss.If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.
    • C-E should be high in at least one direction.
    • B-E may be high or around 50 ohms but should not be near 0.
    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.
    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.
    Of course, not much else will work either.
    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.
    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.
    If none of this proves fruitful, it may be time to try to locate a schematic.
    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.
  • hope this helpout.....


    Jul 08, 2010 | GE 25GT240 25" TV

    1 Answer

    Wont turn on power light flashes 4 times


    Hello,

  • A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!
    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement (including slo-blow if that is what was there originally). Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem (e.g., if the new fuse is not slo-blow and is blown by the degauss circuit inrush current but nothing is actually wrong).
    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:
    • Degauss Posistor - very likely.
    • Horizontal output transistor.
    • Power supply regulator if there is one.
    • Power supply chopper (switchmode) transistor if there is one.
    • Diode(s) in main bridge
    • Main filter capacitor(s).
    You should be able to eliminate these one by one.
    Unplug the degauss coil as this will show up as a low resistance.
    First, measure across the input to the main power rectifiers - it should not be that low. A reading of only a few ohms may mean a shorted rectifier or two or a shorted Posistor.
  • Test the rectifiers individually or remove and retest the resistance.
  • Some sets use a Posistor for degauss control. This is a little cubical (about 1/2" x 3/4" x 1") component with 3 legs. It includes a line operated heater disk (which often shorts out) and a PTC thermister to control current to the degauss coil. Remove the posistor and try power. If the monitor now works, obtain a replacement but in the meantime you just won't have the automatic degauss.If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.
    • C-E should be high in at least one direction.
    • B-E may be high or around 50 ohms but should not be near 0.
    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.
    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.
    Of course, not much else will work either.
    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.
    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.
    If none of this proves fruitful, it may be time to try to locate a schematic.
    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

  • hope this helpout....


    Jul 07, 2010 | Philips Televison & Video

    1 Answer

    It is not coming on


    Hello,

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!

    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement (including slo-blow if that is what was there originally). Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem (e.g., if the new fuse is not slo-blow and is blown by the degauss circuit inrush current but nothing is actually wrong).

    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:

    Degauss Posistor - very likely.
    Horizontal output transistor.
    Power supply regulator if there is one.
    Power supply chopper (switchmode) transistor if there is one.
    Diode(s) in main bridge
    Main filter capacitor(s).

    You should be able to eliminate these one by one.

    Unplug the degauss coil as this will show up as a low resistance.

    First, measure across the input to the main power rectifiers - it should not be that low. A reading of only a few ohms may mean a shorted rectifier or two or a shorted Posistor.

    Test the rectifiers individually or remove and retest the resistance.

    Some sets use a Posistor for degauss control. This is a little cubical (about 1/2" x 3/4" x 1") component with 3 legs. It includes a line operated heater disk (which often shorts out) and a PTC thermister to control current to the degauss coil. Remove the posistor and try power. If the monitor now works, obtain a replacement but in the meantime you just won't have the automatic degauss.

    If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.

    C-E should be high in at least one direction.
    B-E may be high or around 50 ohms but should not be near 0.

    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.

    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.

    Of course, not much else will work either.

    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.

    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.

    If none of this proves fruitful, it may be time to try to locate a schematic.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.
    Hope this help....

    Jun 27, 2010 | Televison & Video

    1 Answer

    No power. We had a power outage last night and today no power


    Hello,

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!

    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement (including slo-blow if that is what was there originally). Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem (e.g., if the new fuse is not slo-blow and is blown by the degauss circuit inrush current but nothing is actually wrong).

    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:

    Degauss Posistor - very likely.
    Horizontal output transistor.
    Power supply regulator if there is one.
    Power supply chopper (switchmode) transistor if there is one.
    Diode(s) in main bridge
    Main filter capacitor(s).

    You should be able to eliminate these one by one.

    Unplug the degauss coil as this will show up as a low resistance.

    First, measure across the input to the main power rectifiers - it should not be that low. A reading of only a few ohms may mean a shorted rectifier or two or a shorted Posistor.

    Test the rectifiers individually or remove and retest the resistance.

    Some sets use a Posistor for degauss control. This is a little cubical (about 1/2" x 3/4" x 1") component with 3 legs. It includes a line operated heater disk (which often shorts out) and a PTC thermister to control current to the degauss coil. Remove the posistor and try power. If the monitor now works, obtain a replacement but in the meantime you just won't have the automatic degauss.

    If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.

    C-E should be high in at least one direction.
    B-E may be high or around 50 ohms but should not be near 0.

    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.

    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.

    Of course, not much else will work either.

    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.

    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.

    If none of this proves fruitful, it may be time to try to locate a schematic.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    Hope this help....

    Jun 21, 2010 | LG 42PC3D 42 in. Plasma Television

    1 Answer

    Tv wont turn on?


    Hello,
    first you have to open the back cover of the television to check for blown fuses.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!

    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement (including slo-blow if that is what was there originally). Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem (e.g., if the new fuse is not slo-blow and is blown by the degauss circuit inrush current but nothing is actually wrong).

    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:

    Degauss Posistor - very likely.
    Horizontal output transistor.
    Power supply regulator if there is one.
    Power supply chopper (switchmode) transistor if there is one.
    Diode(s) in main bridge
    Main filter capacitor(s).

    You should be able to eliminate these one by one.



    Test the rectifiers individually or remove and retest the resistance.


    If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.

    C-E should be high in at least one direction.
    B-E may be high or around 50 ohms but should not be near 0.

    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.

    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.

    Of course, not much else will work either.

    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.

    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.

    If none of this proves fruitful, it may be time to try to locate a schematic.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.
    But if otherwise your power supply board is dead, It can be dead at anytimes.Tries websites Shopjimmy.com,Ebay.com to buy a refurbish power supply board for the replacement.
    Hope this helps....

    .

    Jun 05, 2010 | Zenith R57W46 57" Rear Projection...

    1 Answer

    Our TV suddenly stopped working and will not come back on


    Hello,

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages.However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!

    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement (including slo-blow if that is what was there originally). Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem (e.g., if the new fuse is not slo-blow and is blown by the degauss circuit inrush current but nothing is actually wrong).

    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:

    Degauss Posistor - very likely.
    Horizontal output transistor.
    Power supply regulator if there is one.
    Power supply chopper (switchmode) transistor if there is one.
    Diode(s) in main bridge
    Main filter capacitor(s).

    You should be able to eliminate these one by one.

    Test the rectifiers individually or remove and retest the resistance.

    If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.

    C-E should be high in at least one direction.
    B-E may be high or around 50 ohms but should not be near 0.

    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.

    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.

    Of course, not much else will work either.

    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.

    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.

    If none of this proves fruitful, it may be time to try to locate a schematic.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    But if otherwise your power supply board is died, It can be dead at anytimes.Tries websites Shopjimmy.com,Ebay.com to buy a refurbish power supply board for the replacement.
    Good luck....

    Jun 05, 2010 | iLO 3200 32 in. LCD Television

    1 Answer

    No power


    hello,
    First check if the TV plug is connected to the mains socket.
    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!

    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement (including slo-blow if that is what was there originally). Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem (e.g., if the new fuse is not slo-blow and is blown by the degauss circuit inrush current but nothing is actually wrong).

    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:

    Degauss Posistor - very likely.
    Horizontal output transistor.
    Power supply regulator if there is one.
    Power supply chopper (switchmode) transistor if there is one.
    Diode(s) in main bridge
    Main filter capacitor(s).

    You should be able to eliminate these one by one.

    Unplug the degauss coil as this will show up as a low resistance.

    First, measure across the input to the main power rectifiers - it should not be that low. A reading of only a few ohms may mean a shorted rectifier or two or a shorted Posistor.

    Test the rectifiers individually or remove and retest the resistance.

    Some sets use a Posistor for degauss control. This is a little cubical (about 1/2" x 3/4" x 1") component with 3 legs. It includes a line operated heater disk (which often shorts out) and a PTC thermister to control current to the degauss coil. Remove the posistor and try power. If the monitor now works, obtain a replacement but in the meantime you just won't have the automatic degauss.

    If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.

    C-E should be high in at least one direction.
    B-E may be high or around 50 ohms but should not be near 0.

    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.

    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.

    Of course, not much else will work either.

    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.

    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.

    If none of this proves fruitful, it may be time to try to locate a schematic.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.
    Good luck

    May 21, 2010 | Samsung HCN4226W 42" Rear Projection...

    1 Answer

    No picture


    hi,
    this will require you opening the back cover of the television with the use of an ohmmeter to read components.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!

    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement (including slo-blow if that is what was there originally). Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem (e.g., if the new fuse is not slo-blow and is blown by the degauss circuit inrush current but nothing is actually wrong).

    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:

    Degauss Posistor - very likely.
    Horizontal output transistor.
    Power supply regulator if there is one.
    Power supply chopper (switchmode) transistor if there is one.
    Diode(s) in main bridge
    Main filter capacitor(s).

    You should be able to eliminate these one by one.

    Unplug the degauss coil as this will show up as a low resistance.

    First, measure across the input to the main power rectifiers - it should not be that low. A reading of only a few ohms may mean a shorted rectifier or two or a shorted Posistor.

    Test the rectifiers individually or remove and retest the resistance.

    Some sets use a Posistor for degauss control. This is a little cubical (about 1/2" x 3/4" x 1") component with 3 legs. It includes a line operated heater disk (which often shorts out) and a PTC thermister to control current to the degauss coil. Remove the posistor and try power. If the monitor now works, obtain a replacement but in the meantime you just won't have the automatic degauss.

    If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.

    C-E should be high in at least one direction.
    B-E may be high or around 50 ohms but should not be near 0.

    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.

    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.

    Of course, not much else will work either.

    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.

    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.

    If none of this proves fruitful, it may be time to try to locate a schematic.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.
    Good luck...

    May 21, 2010 | Samsung SyncMaster 323T 32 in. HD-Ready...

    1 Answer

    Wont turn on


    Hello,

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.

    Note that it *may be* useful to replace a fuse the *first* time it blows (though it would be better to do some basic checks for shorted components first as there is a small chance that having a fuse blow the second time could result in additional damage which would further complicate the troubleshooting process). However, if the new one blows, there is a real problem and the only use in feeding the TV fuses will be to keep the fuse manufacturer in business!

    Sometimes, a fuse will just die of old age or be zapped by a power surge that caused no damage to the rest of the TV. However, it must be an EXACT replacement. Else, there could be safety issues (e.g., fire hazard or equipment damage from too large a current rating) or you could be chasing a non-existent problem.

    If the fuse really blows absolutely instantly with no indication that the circuits are functioning (no high pitched horizontal deflection whine (if your dog hides under the couch whenever the TV is turned on, deflection is probably working).) then this points to a short somewhere quite near the AC power input. The most common places would be:

    Degauss Posistor - very likely.
    Horizontal output transistor.
    Power supply regulator if there is one.
    Power supply chopper (switchmode) transistor if there is one.
    Diode(s) in main bridge
    Main filter capacitor(s).

    You should be able to eliminate these one by one.

    Unplug the degauss coil as this will show up as a low resistance.

    First, measure across the input to the main power rectifiers - it should not be that low. A reading of only a few ohms may mean a shorted rectifier or two or a shorted Posistor.

    Test the rectifiers individually or remove and retest the resistance.

    Some sets use a Posistor for degauss control. This is a little cubical (about 1/2" x 3/4" x 1") component with 3 legs. It includes a line operated heater disk (which often shorts out) and a PTC thermister to control current to the degauss coil. Remove the posistor and try power. If the monitor now works, obtain a replacement but in the meantime you just won't have the automatic degauss.

    If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it.

    C-E should be high in at least one direction.
    B-E may be high or around 50 ohms but should not be near 0.

    If any readings are under 5 ohms, the transistor is bad. The parts sources listed at the end of this document will have suitable replacements.

    If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it. The fuse should not blow with the transistor removed.

    Of course, not much else will work either.

    If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor (assuming it is not failing under load), it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.

    Look inside the TV and see if you can locate any other large power transistors in metal (TO3) cans or plastic (TOP3) cases. There may be a separate transistor that does the low voltage regulation or a separate regulator IC. Some TVs have a switchmode power supply that runs off a different transistor than the HOT. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed.

    If none of this proves fruitful, it may be time to try to locate a schematic.

    A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.
    GOOD LUCK...

    May 21, 2010 | Samsung HCL4715W 47" Rear Projection...

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