Samsung PN64E8000 won't come on

[BlueAutumn]

I turned on the TV and and it was on for about 5 or 10 minutes and then went dead. There are no lights, no sound, no picture. What do you think? Power Supply?

[tom66]

Re: Samsung PN64E8000 won't come on

A TV this new is not covered by warranty?
If it's completely dead, I'd look at the power board.

[freakaftr8]

Re: Samsung PN64E8000 won't come on

Check for shorted diodes near a 6 pin voltage regulator that's mounted to a heat sync on that power board.

[BlueAutumn]

Re: Samsung PN64E8000 won't come on

Unfortunately it is about 15 months old, so out of warranty. Thanks to both of you. I'll check the power board and diodes.

[BlueAutumn]

Re: Samsung PN64E8000 won't come on

Replaced the power board. The TV worked fine for two days but now will not come on without unplugging the TV and letting it sit for at least 10 minutes first. If I don't unplug it, wait, then plug it back in, the standby light blinks but TV never powers on.

[nwcs]

Re: Samsung PN64E8000 won't come on

I know this is a old thread but I have this TV in and I would like to try and repair it. It turns on no picture. I can not verify if there is sound since I do not know what input it is on. I have done the following: VS is 3.1V, VA is 0V, VSC is 0V and VE is 5V. I get all of the correct voltages from CN 801 but I do not get VS-ON or PS-ON at CN 802. CN 805 I get 5V at VA and 15 V but no VS. I am thinking y main and x main replacement but want to bounce it off the forum. The logic main led has a 5 second blink. I did use the fast track guide to trouble shoot.

[Nick's Tvs]

Re: Samsung PN64E8000 won't come on

I doubt your new power supply failed again, it is very possible you have a bad Y sustain. What is the LJ92- part number for your Y main? If you could also upload some pictures of the back of the tv, that would help as well.

[nwcs]

Re: Samsung PN64E8000 won't come on

There are two and not marked which one is for this tv. They are Lj92-01780A/B/C/D (58DS) and 01789A/B/C/D (63DS).

[Nick's Tvs]

Re: Samsung PN64E8000 won't come on

Ok picture 2 you have your Y-sustain board and 2 skinny boards called buffers attached to it. So looking at the tv from the back, your Y-sustain board will always be on the left side and your X/Z on the right. After making sure everything has been unplugged for a while, unscrew the Y-sustain and check the pins under that green transformer. I have had a similar model with cracked solder joints on both the Power supply and on the Y-sustain board. If the transformer does not have cracked joints, look at the large diode and transistor pins along with heat sink joints. If still nothing, you could do a quick check on the X/Z sustain for bad solder joints as well.

[nwcs]

Re: Samsung PN64E8000 won't come on

Sorry it took me so long to respond, I did not know anyone had answered it. I checked y buffer and x main for bad solder. All looked good.

[freakaftr8]

Re: Samsung PN64E8000 won't come on

Possibly buffer board mosfets shorted? ?

[nwcs]

Re: Samsung PN64E8000 won't come on

I think I already checked that but I will do it and get back to you.

[freakaftr8]

Re: Samsung PN64E8000 won't come on

Sorry not buffer mosfets I meant buffer ic's

[nwcs]

Re: Samsung PN64E8000 won't come on

Checked all the buffer board IC's and they are all good.

[Nick's Tvs]

Re: Samsung PN64E8000 won't come on

Ok lets start back to the beginning then. Lets test that new power supply and make sure that is has not failed.
Unplug the ribbon cables from the Y and the X sustain boards but keep the large connectors plugged in. Do you get proper VS and VA voltage?
If yes then Power supply is still good.
If no then disconnect the large connector from power supply to sustain and do it again. You should at least see the voltages spike up to 200 or so and 60 or so for VS and VA and then slowly come back down.
If not then do the following

Disconnect all connectors from the Power supply except the one going to and from the logic board. I believe your connector going to the Logic board will have the following pins:
VS-ON
PS-ON
VS-CON
GND
D5.3V
D5.3V

You need to short the following pins together:
PS-ON to ground and VS-ON to 5volt line
The easiest way to do this is to disconnect the connector between power supply and logic on the logic end and to use either a low ohm resistor or the old legs of components to bridge in the holes of the connector.

Once this is done you can go ahead and plug the AC end back in and then plug in your set. If all goes well, you should get good readings on your VS and VA lines.
IF you still don't get a good reading then your new power supply went out.

[nwcs]

Re: Samsung PN64E8000 won't come on

If you mean unplug from the logic main then I get a new issue. I get 1.2V from VS and 0.00V from VA and the logic main led blinks one fast and one long blink three times and the power supply clicks. If I unplug the large connector from the power supply same issue and no spike in voltage. I shorted the ps-on and vs-on like you said and same clicking from ps and no vs or va. So I guess the power supply failed. I will order one and see if that fixes issue. Thanks.

[nwcs]

Re: Samsung PN64E8000 won't come on

Well, I wish I had pulled the power supply board and looked. It has burnt traces and a blown transistor QS810. Anyone know the value of it>

[ReeceyBurger123]

Re: Samsung PN64E8000 won't come on

The PN of it is written ln the front of it. IMO as your not that experienced I would recommend you replace the whole PSU as that transistor going bad could have damaged alot of other things.

[nwcs]

Re: Samsung PN64E8000 won't come on

actually I have replaced these in the past but I agree I will just replace it.

[nwcs]

Re: Samsung PN64E8000 won't come on

Got the power supply repaired and at first when I turned it on I got a good picture for about 1 minute then it would turn off then back on a couple of times then stay off or at least the picture would stay off. If I removed power from the tv then put it back it would do the same thing. Now it turns on and I get no picture and the logic main led would blink rapidly like it should then shut off and go to the slow blink. I verified that VS, VA, VE and VSC are all correct until it would shut off then they would drop drastically. Now after checking the voltages it is working properly. I am not sure what to make of it. I am not sure if I have another board problem. I am interested in fixing this but am by no means a plasma tv specialist so I am reaching out for any help. So far this group has been a lot of help and really appreciate it.