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Author Topic: TV Vertical problems, need repair advice  (Read 544 times)

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snappleman

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TV Vertical problems, need repair advice
« on: February 20, 2017, 10:15:04 pm »
I picked up a standard TV for playing Neo Geo, console and GroovyMame games, and I noticed the top of the screen has horizontal lines going across it. They're not always noticeable (as you can see in the pics) and the stuff playing at the place where I got it didn't show the lines. Anyway I did a whole bunch of research and it all seems like it's the vertical output section's fault, either a capacitor or the vertical IC. The problem I have is I am completely inexperienced with this stuff.

So far I've gotten really good at discharging this TV by grounding a stick mounted screwdriver to the grounding wire on the tube, so that's not a problem. I've tried adjusting a couple pots that are on the board, very slight adjustments at a time, to see if that fixed anything (the pot labeled V.POS1 seemed like the best place to start) but neither pot seems to do anything. The second pot is by the flyback so I really don't want to mess with that since I assume it might have something to do with high voltage.

None of the caps look bad, but I see some discoloration on the board near the vertical section. Anyway I'd really appreciate some advice before I go trying to solder something on this. Also it might be smarter to just get another TV but I live in a crowded city that makes looking for and transporting big TVs a real pain, so if I can fix this one I'd much prefer that (also I really love the picture and input options).

Here's the service manual for it: https://drive.google.com/file/d/0Bw7UFSXj9Jw9Vzdia2xqVnFIS0E/view?usp=sharing

And here are some photos:


No lines over dark colors.



Most MVS, N64, SNES, PS2 games look like that. Anywhere from 1-3 lines that don't fold the image. With GroovyMame I can adjust the screen geometry in such a way that I see no lines or distortion. I could live with this if I had to, but I have the feeling something like this would only get worse if untreated.



NES, Genesis/SegaCD, PCEngine and VHS/DVD players show all those lines, and the images fold over the back.

Here are pictures of the chassis:


and the vertical output section:



The board looks way discolored there around C417, I don't know if that's normal or not, I have no experience with this stuff.

Anyway sorry for the long post. If anyone here has advice they can give me on what looks wrong or what can be fixed/swapped etc. I'd greatly appreciate it. Thanks!


EDIT - The manual lists the parts around the vertical IC as:

C409 - 50V 10YK
C417 - 100V 0.22 MMTS
C422 - 100V 0.1 MMTS

I googled all those values and can't find anything on them that isn't linking to this service manual.
« Last Edit: February 20, 2017, 10:22:33 pm by snappleman »

Paradroid

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Re: TV Vertical problems, need repair advice
« Reply #1 on: February 24, 2017, 01:58:55 am »
So, you were able push the image down and make the lines disappear using GroovyMAME?

If so, you could do the same trick with your consoles using an Extron RXi (provided you're running RGB for everything).

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snappleman

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Re: TV Vertical problems, need repair advice
« Reply #2 on: February 28, 2017, 01:13:05 am »
Thanks, I'll definitely look into that. I'm also going to change out the easy to swap components and see how that goes. GroovyMame doesn't display perfectly with every game, though, there are still many games (like vertical shooters) which still scroll far up enough to flip around the back.

  
 

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