No power I have no power from Hot side. The power supply board is taken off from tv.When plug into a variac, power up, white wire(goes to fuse) measure normal. The black wire measured low(0.6v). TPD6 w.r.t. hot ground measured nothing.The only thing I've done is to de-solder Q801 becuase it diode tested abnormal in circuit.But tested correct out of circuit so I solder it back.What can be wrong? Thanks in advance.

When you say getting 51 volts to power fuse, I assume you're using the red lead from the multi meter at the fuse next to the power plug, but where are you putting the negative lead from the multimeter? If you're using frame ground this won't give a correct reading, in fact you will get around 50 VAC, you need to use the anode side of the bridge rectifier to get a reading or the neutral side of the power line. Does the fuse test good? if it's good measure across the B+ capacitors but be VERY careful getting that measurement as it will be close to 400 VDC if PMW is active, voltages like that can be dangerous. If you had a power surge there is a good chance the hot side of the power board was hurt, easy fix may be replacing the board, another issue this model set has is corrupt data in the EEPROM located on the main board, this can make the set appear totally dead

one side is hot 120v other side is neutral

Thunderstorm over the coax or /and the power supply measure the power supply by a defect cannot be measured anymore over an analog hand adjustable power Variac transformer from 0 to 240 volt. because a protection can be given by a defect t-con board (as suggestion) but the variac its good to bypass/ overhaul the build-in safety protection circuit inside the power supply board then sometime if there else are broken or bad components hard to find they can be sometimes intentional burning out or become warmer by twist the variac power slowly up from of zero volt until the max necessary voltage T-con boards that can have a problem with smd components sometimes they can burning out the defects but its only to do if there is no equipment to measure repair or nothing was to find without a service manual or other optical defects , an short-circuit tuner also by thunderstorm sometimes only the little ceramic capacitors what hangs to earth (chassis) if the thunder energy was coming over the antenna coax cable. the power supply can stand in a safe protection mode. then a refurbished board somewhere can be necessary that will give a reset to release the protection mode in the power supply.. Thunderstorm can be strange and much different and i have had 2 times repairing when there was only 1 ceramic short-circuit ceramic capacitor to find thats was with one leg is( on cold-earth) on the chassis. as the one and only defect component. A time in a TV and 1 time in a radio , sometimes its realy strange but comes it over the power supply its hard to find because of more recurring complaints if partial repair in smd circuits. hard to do without necessary tools.

Then its working primary good, the fuses but secundary can be bulged capacitors convextopped or leaking ones on the print ? a mos-n-fet can be damaged also there are fuse-resistors inside little circuits to protect to tuner and other places but also, the green colored versions of korean 3w resistors could have bad end wirecaps on it it could be the case but capacitors of Samsung are allways bad in-between 4 a 5 years of the most models tv, s look for replace with 10 volt higher caps and 120 degrees typos . solder pads of heat-carrying active components and loose components by bad solderings cold solder bath on the factory on some places.
first measure for junction of the diodes secundair if there is one shorted it will also stand in protect-mode , if you not find the problem , you can take a variac in order to circumvent the short-circuit protection hihihii then its burning out a few components where it became wrong so ill do that in the early times of the first CRT with sda scl and memory codes and protection in the digital era in tv from analog CRT tv i know that it was very different to repare a 30 years ago TV with variac but if you slowly higher the power on you can in serial place a lamp of 200W between the AC to the power supply to see with a temperature measurement witch active component could be bad.

yes after to the fuse you must have a reading of 120vac if none the fuse get busted. if the 120v is present then it will goes through the rectifier bridge diode and primary capacitor of the power supply board to have an stand by voltage at the power supply board. when you press the power button it will send signal voltage coming from the main board to turn on the power supply board. the you will need to get an output voltage at the power supply board of 5v dc, 12v-16vdc and 24v to turn on the all the circuit, the main board sound amplifier and the inverter board for screen back light.if you can get those supply the tv unit will not turn on.

Is the red light on? Does it change to blue when you press the power button?

If the red light is lit, part of the power supply is working to provide the standby voltage. If it is not lit at all, check to make sure power cord from the mains power (wall outlet) cord is securly and fully inserted in the back of the set. If it still remains dark, the power supply is the primary suspect.

If no light, initially check the fuse, it is 5 Amps and a little smaller than a mini marshmallow. It is located on the right side of the board as you face the back of the set. It will be in the vicinity of the connector comming up from the power cord adapter. To test this, check other voltages as described below first, as the power supply board must be removed to get at the bottom leads of the fuse.

If the light simply remains red no matter what button is pushed, the power supply board is the first place to check for faults. If you have a voltmeter, unplug the set and remove the center plastic panel of the set, this reveals a metal plate, which is retained by three more screws along the bottom. The base can remain in place.

With that plate removed, use care when it is plugged in as there is lethal v voltage potential on the right side of the opening as you are facing the back of the set. There will be two boards, the one on top with the metal plates visible is the power supply. The lower board processes the inputs into video and audio components and is the "A&D board", These are important to know if you are buying them off of Ebay or other internet vendor.

With the set unplugged look for a mounted connector on the left side near the top where 2 sets of multiple wires come out of it and plug into a pair of connectors on the lower side of the power supply board (Black,red and another color) There are multiple red and multiple black wires- in the mounted connector, there is just enough room to insert a probe tip with a little bit of force, just enough to ensure the tip is in contact with the conductive connector in 1 each of the black; insert the black test lead from the meter, and the red test lead of the meter to one of the red in the larger mounted connector. The several red wires attach to the same copper pad on the power supply board so only one measurement needs to be taken to determine if power is available for the inverter board or boards. The black wires attach to one pad as well. With the meter set to it's highest DC voltage scale, plug the set back in and switch to lower scales as needed to ***** a avoltage measurement. see if you have a voltage in the area of 24 volts. If you do- check the fuse(s) on the inverter board or capacitors of same boards (depends on production run.

If you have 24 volts, the blue pilot lamp should be lit on the front. You can see on the face of the set if the tubes are lit or not. If you have 24 volts but no light- the fault is with the inverter or the CCFL tubes. The inverter should be pretty obvious if it is the issue because the capacitors will have bulging tops. The chip fuse for each section should checked for continuity If there is, the fuse is good. These require a high ripple current type of electrolytic capacitor. A general purpose type will not last in this location.

If the set has the CCFL's lit, but no response to an input signal, move the test leads carefully, or unplug set to move them to the corresponding red and black wires of the bundle that plug just above the paired sets that go to the inverters, the upper set has 3 red, 3 black, and 2 other colors on the connector. You should see a voltage measuring between the red and the black. If no voltage, or less than about 3 volts, the power supply board is at issue. If the voltage is greater than that, the A&D board is likely at fault, this is the board that is below the power supply board..

This is an ITC 222 chassis and what happens is the flyback High Voltage transformer develops bad solder connections and blows a small fuse located next to it. To repair, first UNPLUG THE TV and after taking the back off the set look for the board that has the big red wire coming out of it and going toward the inside of the tv. The big red wire originates from the High Voltage transformer. Care has to be taken to remove the board which is clipped in by plastic tabs. Also remove plugs that hold the board back from turning the board upside down. Be careful with the two ribbons and remove and put back carefully. When you get the board turned upside down look at the connections at the bottom of the High Voltage transformer...they will appear to have rings around them which look like the solder it not connecting on some of the pins. After soldering the pins if you look just to the right of the transformer (looking at the component side) there will be a couple of small brown boxed shaped components. These are fuses. If you have an ohm meter and turn the board to the solder side again and measure continuity across each of these fuses and one of them could be open and not measure continuity. Since it would take a while to get a fuse like this I use a trick: I get an AC power cord and strip it back with my knife and get just one small strand of the copper wire and solder it over the bad fuse. I strand like this is about 5 amps. After doing all this put the board back in its place and plug up whatever you unplugged and turn the set on and the double image and bow should be gone. If not then you have a convergence power supply board bad which is directly above the board you fixed to the far left. But most of the time it is just as I mentioned: the solder connections and the fuse

CAREFULLY Measure the voltage on both sides of the fuse to make sure that the fuse is actually good.

No fix?

disconnect and reconnect the wires from the low voltage and control side of the power supply board.

No fix?

Throw it in the garbage.

Most TVs today use a "hot-chassis" design and a switch-mode power supply. You should use an isolation transformer when doing any service work on a TV. This helps protect you and your test equipment, and can prevent accidental damage to the TV by grounding parts to the wrong point.

Hot-chassis sets use two different grounds. The power supplies have one ground reference for the primary side (hot ground) and a different point for the secondary (cold ground). The point you pick will depend on what part of the TV you're measuring.

If you are troubleshooting a dead set and working on the primary side of the power supply, use the negative lead of the large electrolytic capacitor you'll find near the AC input connection. There's almost always a bridge rectifier and filter cap (300 to 400 uF range, 180 to 250 volt rating, so physically pretty large) in that area to make the raw DC. That's a guaranteed good hot ground. Sometimes the set will have a labeled hot ground point right on the circuit board for you.

For measurements on the secondary (output) side of the supply, almost any shield can is ground. The tuner cover is a good choice.

you are so lost... a short in anything after the power supply will shut down the horizontal driver signal. first check to see if horizontal output transitor is shorted. If not it should have about 110 volts dc on it. if not go back to Power suppy ...many things start here...check to see if you micros got power a 5v heatseeked regulater is common bad. also the startup circuits can be tricky...in the power suppy. I look for a kit online for power supplies ...they give you about every that fails. or you can start buying boards...best bet it is take to a professonal for you my freind havent a clue. CrazyLarry