Hi, I wonder if someone can help me with this beast.
Ive been repairing plasma TVs for years but this one is extremely stubborn and gives me lots of grief
Y sus: EAX61319402 EBR63039802, came up with open safety resistor 2.2 ohm supplying V sustain voltage RAMP UP mosfet. I didn't find any other issues on that Y sus so just replaced the resistor but it went again. The fault was very poor picture with red sparklies and no image reset (so-called 'black hole' on display) The waveform on the scope looked bad, but I read sustain pulses and scanning wave, obviously no 400V reset pulse due to no supply to ramp transistor
I was advised by other engineers that I should replace all other sustain IGBTs even if the read correct on the meter, so I did so, but powered up the TV and there was 2 big bangs- this time the newly fitted igbts on Y sus blew up and the Z sus (4x igbts blew)
Repaired the Z sus but was told that if I repair Y sus again, blue ceramic disc caps must be changed as well, so I had replaced them with 4x 101k 1kV coz i didnt have the right ones (102k, 1kV), this time round the unit comes on, but theres almost nothing on the screen, on the scope, Y/Z sus pulses look ok, but reset pulses are very slanted and the main initialize pulse missing again, obviously the bloody resistor R426 died again
I checked all circuitry around the RAMP UP Q, all read good on the meter, does someone have any cure for this fault, sustain heatsinks are cold as stone only energy recovery mosfets are heating up, but mostly, no raster.
Vs, Vy-, Vscan all correct, I replaced all original Qs with RJP63F3 which normally work on SUS UP half as they are rated 600V 200A in pulse any ideas any plasma man there to help?
thanks a million
Paul
Ive been repairing plasma TVs for years but this one is extremely stubborn and gives me lots of grief
Y sus: EAX61319402 EBR63039802, came up with open safety resistor 2.2 ohm supplying V sustain voltage RAMP UP mosfet. I didn't find any other issues on that Y sus so just replaced the resistor but it went again. The fault was very poor picture with red sparklies and no image reset (so-called 'black hole' on display) The waveform on the scope looked bad, but I read sustain pulses and scanning wave, obviously no 400V reset pulse due to no supply to ramp transistor
I was advised by other engineers that I should replace all other sustain IGBTs even if the read correct on the meter, so I did so, but powered up the TV and there was 2 big bangs- this time the newly fitted igbts on Y sus blew up and the Z sus (4x igbts blew)
Repaired the Z sus but was told that if I repair Y sus again, blue ceramic disc caps must be changed as well, so I had replaced them with 4x 101k 1kV coz i didnt have the right ones (102k, 1kV), this time round the unit comes on, but theres almost nothing on the screen, on the scope, Y/Z sus pulses look ok, but reset pulses are very slanted and the main initialize pulse missing again, obviously the bloody resistor R426 died again
I checked all circuitry around the RAMP UP Q, all read good on the meter, does someone have any cure for this fault, sustain heatsinks are cold as stone only energy recovery mosfets are heating up, but mostly, no raster.
Vs, Vy-, Vscan all correct, I replaced all original Qs with RJP63F3 which normally work on SUS UP half as they are rated 600V 200A in pulse any ideas any plasma man there to help?
thanks a million
Paul
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