Samsung 50inch Plasma - colored sparkles (videos in thread)

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

Great! Yrr is the one we are looking for . Is there also a Yfr?

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

It took a bit of looking, but yes there is a YFR as well. Its hidden under the metal brace. You may be able to see it from one of the pictures (possibly the side shot that i did), but if not i can snag a picture of that too. Its a tight space though for sure.

Its located on a board which extends vertically out from the Y SUS board, sort of like a daughter board would.

Does that make sense?

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

Great. Now, I want you to set up the TV so it is facing a mirror which you can see, or get a friend to tell you when the picture is good. Can you do that?

The first step is to correct the mistakes the TV technician made in randomly adjusting the voltages. I assume you have a digital multimeter - if not you need to go out and get one. (An analogue one will not suffice.)

On the back of the plasma panel (inside it) there will be a sticker telling you what voltages the Vs and Va should measure (e.g. Vs=215V, Va=68V.) These voltages control the plasma discharge inside the panel. If they are more than 5% out either way, the picture will look very poor. There may be other voltages such as Vsc and Ve; these are important too, but not as important as Vs and Va.

On the power supply there should be two potentiometers which allow the adjustment of these voltages. It's crucial these are in spec before the timings are changed. Post a picture of these potentiometers and of your multimeter.

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

do you mean you want pictures while measuring the voltages or do you just want to see what type of multimeter that i have?

i dont think i can hold the DMM in place to show the voltages and snag a pic ... but i can for sure tell you what i'm getting

i can do all of what you said when i get home tonight.

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

do you mean you want pictures while measuring the voltages or do you just want to see what type of multimeter that i have?

i dont think i can hold the DMM in place to show the voltages and snag a pic ... but i can for sure tell you what i'm getting

i can do all of what you said when i get home tonight.

I want to see the power supply, around the area where the connectors go from the power board to the sustain boards on the left and right of the TV (usually the place where the potentiometers are located.) I also need to make sure your multimeter is capable of measuring the 200V or so present on these boards. Most are, but a few aren't.

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

pic of DMM


this is the power board i'm assuming?


another shot of it


trying to get the left and right side angle (respectfully) so you can try to see behind the brace




I believe this is where power comes into the Y SUS board


connections from what i think is the logic board (has most of the inputs on it) to the power board




this is a connection coming from the bottom left of the power board to what appears to be the power cord connection



another shot of the power board connecting to another board in between the power board and the X SUS board (i think)



X sus


here is the tv as a whole


i'm ready to test voltages and return the pentometers to thier original value, but i'm just not sure where the test points are

also i dont want to kill myself

thanks again for your help .. i have my DMM ready to go etc ...

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

Okay, so you have a "China special" DMM. That's okay, but be careful as the probes on these are very dodgy, you can easily slip. Most of the board is safe to touch, apart from the Vs side, and the primary side (where the mains input is.) Still, avoid touching any of it, just in case. I've highlighted the approx. area of the primary side.

For this test, and all future tests unless otherwise indicated, set your multimeter to the 1000V DC range. Move the red lead from the 10ADC jack to the V/ohm/mA jack.

Pic #2 - There appears to be a sticker here. What are the voltages indicated?

Now, the adjustments:

On the sticker you will see a voltage labeled Vs. Do not confuse this with Vset. Vs is typically 180 - 220V DC.

Connect your red probe to the highlighted pin, and black probe into the screw hole. I find it's helpful to try and jam the probe in there, as it will stay there if you apply a bit of pressure. The black probe can sit in the hole. The metal panel is safe to touch, it is grounded.

Measure the voltage. If it is more than 1% out, I would adjust the corresponding Vs potentiometer. Adjust it up very slightly (just a quarter turn, at most.) If it goes down instead of up, reverse the direction of the turn. Turn it until you are satisfied it is within about 1% (or around 2V of the sticker rating.) Don't expect the picture to get immediately better - this TV appears to use at least 5 different voltages and each must be set to the factory default for it to work well.

Report back if this goes well and we can have a look at the other voltages and then the timing adjustments.

[bbjunkie]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

I'm sure you are aware, but for the sake of your poor old DMM i'll say it anyway.

You have the red lead in the port for measuring current, don't forget to move it to the other port before measuring any voltages or damage will occur.

Good luck, you are in good hands with tom66

Jim

<edit> too slow, tom noticed also!

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

Vs was 211-212 prior to adjustment

i got it down to 201-204 depending on how i hold the red tester, lol



this has made the overall picture worse.

i'll post a quick vid of that momentarily.

i have have also now gained a noticeable "bar" of what appears to be more blue sparkles on the left side of the tv.

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

http://youtu.be/N5c3p0lVIys

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

this has made the overall picture worse.

This is normal. Sometimes the picture on these TVs gets a bit worse before you fix them.

I've got to go and revise for my exams now, but I'll be back later to guide you through the rest.

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

Thanks!

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

I just noticed this point is for Vs, use this instead and tweak to the rated 203V. Try and get it as close as possible.

Then, do the same with Va, but tweak to its rating (55V - 80V). Try switching your meter to the 200VDC range - you'll get an extra digit of resolution. Unfortunately we can't do this for the 203V Vs voltage because it's 3V over the 200VDC limit. Although no harm would be done to the meter it would just show over-load... There's also a nice Va test point. Remember not to touch this test point or the Vs test point it can give a nice (or nasty) shock...

Note the Va reading before you tweak it in case you have to return it to the technicians' settings.

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

the sticker for Va is 65 which i have set it to ... it wasnt far off to begin with ... around 63 ish ..

Vs is now a solid 203

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

Okay, now Vset and Vscan need to be adjusted. I've highlighted the test points; I expect the adjustments will be near to these but I can't quite see them. These voltages are less important than the others, but they can still affect the picture. You only need to get them within about 2V. Vscan should be negative, use the 1000V scale to start off with but if the number stays under 200 switch it to the 200VDC. Same for Vset.

Once you have adjusted all of these, it's time for timing... which is relatively simple. I had a Samsung 42" (later version, very cheap inside, B450 series) with a similar problem in that it had sparklies... but it was almost like it remembered the sparkles (it had image retention for several minutes after something showed on the screen) but only on certain scenes. In my case, adjusting Yfr ever so slightly fixed the problem. In my experimentation upon an unwilling LG Plasma (ancient piece of junk...) I found Yfr (LG call it Setup) affects the sparklies and retention and Yrr (Setdn) tends to affect the whole screen (changes the brightness and colours, makes everything funky.)

[muskin]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

Noticed that the cap in his first picture [top right] looks bulged. Might just be camera angle. Just though I would see if he noticed it?

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

tweaked the YRR and YFR a little bit each experimenting back and fourth and have eliminated all the sparkle that was brought back from adjusting the voltages from earlier ...

there are still sparkles there however ... i'd say it looks better than it did before i started, but still not "sparkleless"

now what?

also the blue bar i was talking about earlier (that you can also see in the video) has mostly disappeared however a small portion of it remains in the lower left hand corner.

[dustinarden]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

Noticed that the cap in his first picture [top right] looks bulged. Might just be camera angle. Just though I would see if he noticed it?

which cap?

i can investigate and report back.

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

I noticed that too, but wrote it off as the camera angle. However, I would think a bad capacitor could cause sparklies. OP, with the set off and unplugged, feel the capacitor - if it feels slightly bulged it might be failing. Now, it's a Chemicon, which is a high quality capacitor, and I haven't seen these caps fail yet... but I wouldn't write it off as being impossible.

[tom66]

Re: Samsung 50inch Plasma - colored sparkles (videos in thread)

tweaked the YRR and YFR a little bit each experimenting back and fourth and have eliminated all the sparkle that was brought back from adjusting the voltages from earlier ...

there are still sparkles there however ... i'd say it looks better than it did before i started, but still not "sparkleless"

now what?

also the blue bar i was talking about earlier (that you can also see in the video) has mostly disappeared however a small portion of it remains in the lower left hand corner.

Try adjusting Yrr only, turn it about an eighth. Yfr doesn't have much effect on sparklies.