Samsung hd rear projection tv crt subtle wavy lines on displa

[shelby5041]

This is for the old school tv guys

Its a 2003 samsung rear projection....crt style tv

The picture is bright and good color but it has a very subtle vertical wavy lines on the display that seem to change a bit depending on brightness or color of scene..the wavy lines move a bit...not static......almost seems like some type of interference issue...

Any ideas what would cause this?

I had tv stored in unheated garage for 6 years...i live in michigan

[freakaftr8]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Does the picture get out of focus up on bright scenes? Any subtle snapping or popping sounds when pictures change from bright to dark scenes? Does it do this on every input?

Considering the age of the TV I would start suspecting B+ regulation issues Within the primary side of the power supply

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Picture is great...bright....just has these very subtle wavy vertical patterns ..

Tv is older but remember havent used it in 7 yrs

Im not wanting to fix it...not worth it...just wondering what would cause the issue

Its on All inputs...didnt do it on previous tv so its the tv..not the video source

No popping sounds or any unusual sounds at all while video playing......

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

If i take a pic and post it...the wavy lines are so subtle the posted pic probably would show the lines

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Im trying to find a pic online that looks like my issue

[freakaftr8]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

OK so it's probably not a boost regulation problem but more or less some bad tantalum capacitors and the IF stage. This is the part of the TV that does the frequency modulation to display the image into different frequencies that the circuits can understand. CRT televisions do not use a timing controller or any other circuitry besides a high voltage to low voltage and high voltage flyback transformers, and video processing like Horizontal and vertical oscillators. I suppose the problem could be in the horizontal or vertical output stages or oscillation stages. Snap a picture maybe you would help figure this out

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

freak how do u and others in here know so much .....did u go to school/traininf for it or learn from job....its awesome....the technical knowhow is hard to believe......im just a tinkerer....have no knowledge of how tvs work internally..

[linksys1127]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Contact Mr. Bob on Avsforum.com. Click on forums and go to rear projection forum. He is the rear projection guru. Look for the title “Don’t dump your CRT RPTV”. Post it there. He helped me out!

[R_J]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Is the problem when using the tuner input or with the video inputs? If the problem is there with the video inputs, that eliminates any R.F. or I.F circuits, also does it effect the menu? many times the video and menu signals are seperate untill they get to the crt video drivers. try sending it a different resolution and see how that effects the problem
It most likely a bad cap in the video circuit somewhere, probably one or more of those crappy smd electrolytics
Whats the Model?

[freakaftr8]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

These and Toshiba's were littered with bad tantalum capacitors on the IF modules. Try heating up the video boards with a hairdryer and see if the problem stabilizes.

Good call on the menu R_J. I haven't had my head in one of these in a while.

I learn what I learn since I was a young boy tinkering. Picking up on hobbies and working in a video repair shop here in Sacramento really helped me out a lot in my teens. Everything I know is self tighten and still learning every day just like this damn OLED that I'm working on

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

The video source is the regular video input via rca cables......not the tuner

And im not sure if the wavy distortion lines are present when osd is on or not...im not at house with tv...

I normally dont even mess with crt tvs anymore since they are obsolete and noone wants them out here but i had one sitting in my garage and my friend needed a tv so i gave it to her yesterday and noticed the wavy distortion interference type vertical lines....very subtle..but if you look hard you see them....

Ill look at caps when i can"........all samsung tvs seem to have a lot of issues dont they?

[R_J]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

All it takes is for the output cap on a regulator ic for examble to be weak, and that small amount of ripple at usually a fairly high frequency to get into the video circuit somewhere, and it will show up on the screen.

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Thanks..there are lots of caps on the video and power supply baord...none are visually bulged.all flat tops

It does seem like a interference issue like you said ....it sometimes is worse than other times...and it is present even on blue screen with no video input...so i dont believe its a board issue...its probably a cap issue thats doing this....but there are over 30 caps on these boards...maybe ill try to take a pic and maybe someone can point out an area to concentrate on....

The lines are actually more vertical but do go on odd angles sometimes....they are about 5-7mm wide and spaced equally about the same...i took some pics will post....

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Here is an image from my tv....the horizontal distortion is due to camera

The vertical ones are real....looks much worse in the pic but it shows you what it looks like

[freakaftr8]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Looks like rf or chroma issues. Probably an out of spec capacitor for the crystal oscillator.

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

freak..which board are these caps on that you think coulb be bad?

i cant take a pic.... not with tv now

[R_J]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

That is most likely a bad cap in one of the low voltage regulators, It could be from one of the voltages derived from the flyback or it could be from the switching power supply.
It can't be rf issues if you are not using the tuner input. If the color 3.58 osc was off at all you would have no color, if the frequency was off the tint would be out a mile.
The color osc. is phase locked to the video.
Any chance you can provide the Model Number?

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Model HCN4727W

Its actually a beautiful tv.... i think crt tvs are superior to lcd tvs....no refresh issues and are usually way more reliable and last many years

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

Here is a photo of tv

[shelby5041]

Re: Samsung hd rear projection tv crt subtle wavy lines on displa

And rpts are kid friendly.....lcd tvs are not kid friendly lol.....crack!!!!