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SnakesAndStuff
Joined: 08 Dec 2009
Posts: 38
Location: Jonesboro, AR
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 Posted: Mon Mar 19, 2012 4:34 pm Post subject: Samsung HCP4752W Pin Cushioned |
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I have a samsung HCP4752W that I had previously repaired as listed/discussed here. A few months back this same TV was operating fine... but all of a sudden I head a pop, smelled the magic smoke start coming out of some electronics, and the screen started to zoom in and pin cushion.
Is anyone here familiar with this model/series? I know it is an old TV, but if it is a replacement of an opamp/fusing resistors/etc like the past repair was I don't mind doing it.
Here is a photo of the current condition. The TV is "pin cushioned" and the blue is a little out of convergence. I figured I should tackle the pin cushioning first.
Many thanks in advance.
Last edited by SnakesAndStuff on Sun Apr 08, 2012 1:45 pm; edited 1 time in total |
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JTS1957
Joined: 21 Jan 2009
Posts: 2395
Location: Far, Far Away
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| Posted: Mon Mar 19, 2012 9:23 pm Post subject: |
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If that's supposed to be a crosshatch pattern, you've also got some width/linearity problem(s).
First, does the convergence adjust normally, both with "self focus" and manually (search your model number)? By normally I mean: green is the reference and should not move during convergence adjustments. Both red & blue should have the capacity to be adjusted both up & down AND left & right at the center of the pattern/screen. |
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SnakesAndStuff
Joined: 08 Dec 2009
Posts: 38
Location: Jonesboro, AR
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| Posted: Mon Mar 19, 2012 9:29 pm Post subject: |
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When I use the self focus, it does this. It is supposed to be a square grid.
From reading information from elsewhere it appears that the green stays put and you can only move the red and blue. |
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JTS1957
Joined: 21 Jan 2009
Posts: 2395
Location: Far, Far Away
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| Posted: Mon Mar 19, 2012 10:15 pm Post subject: |
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| SnakesAndStuff wrote: | | the green stays put and you can only move the red and blue. |
I though I just said sumthin like that.
| JTS1957 wrote: | If that's supposed to be a crosshatch pattern, you've also got some width/linearity problem(s).
First, does the convergence adjust normally, both with "self focus" and manually (search your model number)? By normally I mean: green is the reference and should not move during convergence adjustments. Both red & blue should have the capacity to be adjusted both up & down AND left & right at the center of the pattern/screen. |
Key point:
Does the red move BOTH above AND below the green at the center?
Does the blue move BOTH left AND right across the green at the center?
Does the blue move BOTH above AND below the green at the center?
Does the red move BOTH left AND right across the green at the center? |
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SnakesAndStuff
Joined: 08 Dec 2009
Posts: 38
Location: Jonesboro, AR
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| Posted: Tue Mar 20, 2012 3:56 pm Post subject: |
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I apologize, I misunderstood the question.
Yes, I can move the R,G,and B.
I think if I had the pinching corrected I could reconverge correctly.
I can move all 3 colors up, down, left, right on the convergence grid.
Thanks. |
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JTS1957
Joined: 21 Jan 2009
Posts: 2395
Location: Far, Far Away
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| Posted: Tue Mar 20, 2012 6:29 pm Post subject: |
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IF your GREEN is moving during the "convergence" adjustments, then it has a problem, since it is the stand-still reference for the other two colors. Green will move during "geometry" adjustments.
Edit:
Pincushion symptom/cure #1:
Check/replace: Q433? Also C449 charred?
Pincushion symptom/cure #2:
Check/replace: Q371, DZ371, D372, D374 & C372 |
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SnakesAndStuff
Joined: 08 Dec 2009
Posts: 38
Location: Jonesboro, AR
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| Posted: Tue Mar 20, 2012 7:56 pm Post subject: |
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Perhaps I am incorrect in my terminology. I was able to move the green when I entered the grid screen from hitting mute-1-8-3, then hit 8 for the green.
Should I not be able to move it here? Or am I mistakenly thinking I'm changing convergence when I'm really altering geometry? |
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JTS1957
Joined: 21 Jan 2009
Posts: 2395
Location: Far, Far Away
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| Posted: Tue Mar 20, 2012 8:18 pm Post subject: |
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OK, but I believe these require straight horizontal and vertical gridlines before adjusting.
Have you checked the parts in the two sym/cures in my earlier edit?
EDIT: | SnakesAndStuff wrote: | | I head a pop, smelled the magic smoke start coming out of some electronics, and the screen started to zoom in and pin cushion. |
Remember, NO amount of adjusting can properly compensate for defective parts!
Last edited by JTS1957 on Tue Mar 20, 2012 8:25 pm; edited 1 time in total |
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SnakesAndStuff
Joined: 08 Dec 2009
Posts: 38
Location: Jonesboro, AR
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| Posted: Tue Mar 20, 2012 8:20 pm Post subject: |
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Nope, will try to do it tomorrow when I have some time off.
I appreciate the help and I'm not trying to be a bother. I just hope that I'm able to use the correct terminology and convey things correctly.
Hopefully tomorrow I'll get the case off and poke around. |
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SnakesAndStuff
Joined: 08 Dec 2009
Posts: 38
Location: Jonesboro, AR
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| Posted: Wed Mar 21, 2012 3:19 pm Post subject: |
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| Where would these be located? I'm looking on the board labeled BP41 00070A |
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