Samsung PN65F5500 Plasma TV

[fatblond]

Hey, guys hopefully you can help me diagnose a problem.

I have a Samsung PN65f5500 plasma TV that occasionally will go black for a few seconds at a time. While the screen is black, I still have sound but I can't pull up a menu or visually interact with the TV. I checked each of the HDMI connections and internal smart apps and it happens on each of these. These blackouts appear randomly in that it is not dependent on what is on the screen i.e. bright or dark images. It powers on fine.

I have visually inspected all the capacitors and connections and there are no bulges and every cable, ribbon, etc appears to be connected. There does not appear to be any damage to any chips that I can see.

I made two videos of the problem and placed them on youtube.com
https://www.youtube.com/watch?v=oCww7T5DsqY
https://www.youtube.com/watch?v=bu70dyDtRJo

When I described these symptoms to shopjimmy.net, they recommended replacing the y-main and the y-buffers. I did that by getting some salvaged parts from a local company and everything appeared to be working fine for about five days. For three days I left the back cover off the TV and kept it on the floor. However, on the fourth I put it back on the wall mount and on the fifth day, I used the TV for several hours 4 and the problem surfaced again.

At this point I am uncertain as to what could be causing the problem. The main? The power supply? The x main or buffers? Could the parts I bought have been bad? Anything I should check with my multimeter?

I have kept the TV off the mount with the back cover off for now to see if the problem is related to a chip overheating. I will test with a hairdryer tonight as was suggested in one of Tom's posts to see if that can cause the problem.

Any help is greatly appreciated!

[Hamie]

Re: Samsung PN65F5500 Plasma TV

Firstly can you upload a picture of your control board.

Secondly don't by any more boards until you are almost positive it will fix your fault.
Do you have a digital meter?

[fatblond]

Re: Samsung PN65F5500 Plasma TV

Firstly can you upload a picture of your control board.

Secondly don't by any more boards until you are almost positive it will fix your fault.
Do you have a digital meter?

Will do ASAP. I think the control board must be hidden under the main as I have not located it yet.

Definitely not going to buy any more boards for now.

I have a couple digital multi-meters. Just bought a new auto ranging one in fact just to try and diagnose this TV's problem.

[fatblond]

Re: Samsung PN65F5500 Plasma TV

Double checked and I think my the control board might be merged with my main board or else I simply can't find it. Here are some pictures of the back of the TV and the main logic board

[Hamie]

Re: Samsung PN65F5500 Plasma TV

Yeah looks like it.

Ok the sticker above the ysus has the voltages that must be present for the TV to operate.
Vs, va vsc and ve.

Vs and va test points are on the power supply, vsc on the ysus and ve usually on the xmain (zsus)

You need to have the TV powered on and monitor these voltages and see if any drop and rise when the panel goes black then back on

[fatblond]

Re: Samsung PN65F5500 Plasma TV

I will check this this evening. Hopefully the TV will be symptomatic this evening. I had it plugged in last night and running with the back off for a couple hours and no blacking out hiccups.

I will report in with any results.

Thanks a bunch for your help!

[Hamie]

Re: Samsung PN65F5500 Plasma TV

Possibly heat related then, heat each board up with a hairdryer and see it when heating up it starts to fault.
May just be a cold solder joint.

[fatblond]

Re: Samsung PN65F5500 Plasma TV

I checked the voltages coming from the power supply to the y main and it checks out. 217 (read at 216.8) and 56 I believe off the top of my head. Wasn't able to recreate the problem yet to test the voltage during a black out though.

I attempted to use a hair dryer briefly last night but to no avail. Just so I can better trouble shoot do you know a) which board I should focus on, and b) what temperature I should be shooting for? I was getting the main up to ~140but had not blackouts. Should I go hotter?

I think tonight I am going to put the back, back on, and then use a hairdryer to see if I can get the error when ventilation is lower. I will also use my magnifying glass to see if I eyeball a cold solder joint.

Is it possible that hanging the TV on the wall using the vesa mount could exacerbate a bad solder joint? Possibly flexing the unit in some way? Seems like a stretch, pun intended.

Thanks for your help!