Samsung pn64e533d2f has sound no picture

[nwcs]

I have this plasma that the sound is fine just no picture. I have checked the buffer boards for shorts and found none. VA is 55V and VS is 143V roughly have what it should be. I unplugged the y main from the logic main and the voltage is now 217V which is the correct voltage. All other voltages are correct. I took the power supply out and found someone either did some repairs to it or checked so now I think it might be the power supply but I am not sure. I really need some help on this one.

[dick_barton]

Re: Samsung pn64e533d2f has sound no picture

What voltages are given on the LCD panel. Can't quite make them out.

[ReeceyBurger123]

Re: Samsung pn64e533d2f has sound no picture

So with the Ymain in Vs is low and woth it out it rises ? If so the Ymain has an issue. Also in a dark room does the screen glow ?

[nwcs]

Re: Samsung pn64e533d2f has sound no picture

to dick_barton what voltages do you need and to ReeceyBurger123 no glow at all.

[nwcs]

Re: Samsung pn64e533d2f has sound no picture

I was wondering if the logic main can cause this problem.

[martino]

Re: Samsung pn64e533d2f has sound no picture

These sets do have a notorious problem with bad solder joints on the power board,Q804,q805 if I remember correctly,but mainly all components on any heat sinks you need to really take a good look at the solder joints,even if they look good,re solder them.
Also,can we see a pic of the "repair attempt" you saw on the power supply?
Vs 143 volts is too low for sure. What exactly did you unplug to get the Vs to come back up to 215?

[nwcs]

Re: Samsung pn64e533d2f has sound no picture

I will get that back up and get the pictures.

[dick_barton]

Re: Samsung pn64e533d2f has sound no picture

to dick_barton what voltages do you need and to ReeceyBurger123 no glow at all.

There's a label stuck on the back of the panel giving voltages such as VS=xx, VE=xx, VA= xx

[nwcs]

Re: Samsung pn64e533d2f has sound no picture

I unplugged the flat white ribbon cable coming from the logic main to the y main. I hope the picture of the voltages and the repair to the power supply might help.

[martino]

Re: Samsung pn64e533d2f has sound no picture

I would first isolate the powersupply from all other boards and force it on via resistors,somewhere between 500 and 1000 ohm. ps-on to ground with one resistor and vs-on to standby 5 volts with one resistor.
Then measure the vs and va to see if they are correct,if they are I would put a load on them,to see if it can handle that or not.
Thatt way you know what board to target. I suspect the powerboard to be weak at best,considering they have a history to fail,and the repair attempt not looking too professional(solder joints look bad).
I might be staring blind here as all the pn64's I had here had a failed psu.

[dick_barton]

Re: Samsung pn64e533d2f has sound no picture

So as martino said earlier VS is far to low so need to find out why. Have you checked for short/open circuits on your Ymain.
With the set off and all boards connected what resistance do you have from test points:- VSCAN to chassis and SVC_YOUT & SVC_VS to SVC_GND

Don't know how close to your set this Fastrack Guide is but it may help. Courtesy of Tom's Servive Manuals

[nwcs]

Re: Samsung pn64e533d2f has sound no picture

I will try these out tomorrow thanks.

[dick_barton]

Re: Samsung pn64e533d2f has sound no picture

Then measure the vs and va to see if they are correct,if they are I would put a load on them,to see if it can handle that or not.

Can you use two 115v bulbs in series to act as a load for the VS supply?

[martino]

Re: Samsung pn64e533d2f has sound no picture

Can you use two 115v bulbs in series to act as a load for the VS supply?

sure can. Not entirely sure what this psu could pull but I'd say two 100 watt bulbs would be enough of a load to test it.

[ReeceyBurger123]

Re: Samsung pn64e533d2f has sound no picture

Can you use two 115v bulbs in series to act as a load for the VS supply?

Spot on.

[ReeceyBurger123]

Re: Samsung pn64e533d2f has sound no picture

sure can. Not entirely sure what this psu could pull but I'd say two 100 watt bulbs would be enough of a load to test it.

Not even that for these, this set only uses about 210 watts, Vs will be about 160-180w of that Id say.

[ReeceyBurger123]

Re: Samsung pn64e533d2f has sound no picture

No offence here your soldering on the Psu is not good. Get some solder with flux combination and resolder the joints again and clean with Ipa and a toothbrush.

[martino]

Re: Samsung pn64e533d2f has sound no picture

No offence here your soldering on the Psu is not good. Get some solder with flux combination and resolder the joints again and clean with Ipa and a toothbrush.

I think he got it that way.

[nwcs]

Re: Samsung pn64e533d2f has sound no picture

I will have to look for the resistors unless I can use something else. As for the resistance checks here they are:
Vscan to Chassis 3 ohm then it goes slowly down in value
Svc_yout 152 ohm
Svc_Vs 310 ohm then slowly goes down in value
Svc-Gnd .8 ohm.
and the service manual was helpful thanks.

[dick_barton]

Re: Samsung pn64e533d2f has sound no picture

I'm no plasma expert but I would say that Vscan appears to have a low resistance and I wonder if you still have problems with the Ymain or the Y buffers.

If anyone else can offer help at this point it would be appreciated.