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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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When we will give the power to TV, fuse & R502 location resistor burn.


damage can be ascertained from the power regulator, you can check the transistor / STR power regulator, and Diode Bridge (AC-DC), check the Positive and Negative on Elco 220/450 volt power regulator, is there a short circuit? if no, probably from before entering the diode, it can be from thermistor. Hopefully help

Oct 20, 2010 | Panasonic TC-2119R 21" TV

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 Standard (CRT) Televisions

    1 Answer

    Panasonic TV no sound no picture


    THE REGULATOR IC STR ??? OR THE HOT TRANSISTOR MAYBE SHORTED

    Aug 23, 2009 | Philips 27PT543S 27" TV

    1 Answer

    Sony WEGA Trinitron KV-36FV15 does not come on after lightning


    Look for two integrated circuits marked MCZ3001D. These are 16 pin rectangular black plastic "chips". They are static and surge sensitive devices and are a "common" culprit for failure in this chassis. One or both may have failed. Also, if you can, near both of them is a ceramic cased resistor marked 0.1 ohm. If either one of these is open, then the two mosfet regulators (mounted on little individual heat sinks) marked C4834 on the parts are shorted and need to be replaced as well. (There are 4 of these in total in this set, one pair for each MCZ3001D SMPS driver...check all 4 for shorts. If your ohmeter reads zero between any of the pins, then its bad)

    Mar 20, 2009 | Sony KV-36FV16 36" TV

    1 Answer

    Dead set, HOT transistor keeps shorting


    It's the copper coiled magnet on the neck of the crt closest to the front of the tube.

    Dec 21, 2008 | RCA 36V430T 36" TV

    2 Answers

    RCA Chassis TX808D, No High Voltage.


    did you check the horizontal output? then check all zener diode at the hotside! can you give me the number of all power regulator at the hot and cold area!?

    Oct 21, 2007 | RCA E13345 13" TV

    1 Answer

    Does not power on. Q951 charred


    you can look for the model and brand, look for it on the internet and see if you can have the schematic diagram, you're lucky if u can. Lightning will strike first the tuner side, if there is a red blink, the primary side may be okay in switching type regulator, just replacing the charred part may not solve the problem. look for shorted components on the secondary of the power section.

    May 15, 2007 | JVC AV-32230 32" TV

    5 Answers

    High pitch sound


    hi Buddah! heres the solution for the high pitch sound on to your Panasonic TV,,just check if there are some SHORTED RECTIFIER DIODE on the power supply section,

    Dec 13, 2006 | Panasonic CT-36D31 36" TV

    2 Answers

    Question about the voltages.


    what is the question please?

    Oct 20, 2006 | Sanyo DS27510 27" TV

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