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Sony Trinitron KV-32S36 Red Lines in Screen    
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dohclude



Joined: 13 Jul 2009
Posts: 5

PostPosted: Mon Jul 13, 2009 4:43 pm    Post subject: Sony Trinitron KV-32S36 Red Lines in Screen Reply with quote

I was recently given a Sony Trinitron KV-32S36 television. When turned on it displays a raster of Red Horizontal Lines across the screen, but no picture. The audio works. The Red timer LED flashes continuously. With the back of the case removed I can hear a static noise around the tube. I also noticed that there is a large horizontal PCB at the bottom of the set directly in the center that is slightly warped / misshapen (I think it's labeled as the "A Board" in the service manual). I was able to find the service manual for free I am thinking that this is probably the transformer that needs replacing. Can I get a second (or third or fourth) opinion? I have been repairing electronics for a long time and I am confident that I can repair this, but TV's are not my main specialty and I could use some advice as far as a diagnosis so that I don't waste any money on unneeded parts.
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JTS1957



Joined: 21 Jan 2009
Posts: 1652
Location: Far, Far Away

PostPosted: Mon Jul 13, 2009 7:12 pm    Post subject: Reply with quote

Try turning Red Screen (G2) down. If No Change - CAREFULLY try tapping the neck of the CRT - Remember it's glass AND under a vacuum! If it works normally, even for an instant, then returns to what I'd describe as "a Vivid red screen with retrace lines," like the author in the other forum said - Heater/Cathode short in the gun assembly.
dohclude



Joined: 13 Jul 2009
Posts: 5

PostPosted: Tue Jul 14, 2009 8:54 am    Post subject: Reply with quote

well, I tried adjusting the G2 down ever so slightly and the red lines were gone. I only had to barely adjust it down at all. Now I am left with a black screen and no picture and the LED on the front of the set blinks continuously. Now from the service manual I read this:
"Continuous Blink Once A Second, No Pausing As Discussed Above--- No reply from the jungle IC301 (data bus is busy, shorted to ground or held high), IK video path is defective."

So could the jungle IC be the culprit here? I'm planning on discharging the tube and then removing each board to clean the dust from them and maybe check for any cold solder spots or damaged components anyways.
kuhurdler



Joined: 28 Dec 2006
Posts: 2651
Location: Overland Park, KS

PostPosted: Tue Jul 14, 2009 9:03 am    Post subject: Reply with quote

this is a weak CRT. the IK has decided that it's not good enough, and is blanking the video signal.
The only way to fix it is to replace the CRT, but you can extend the life by turning the G2 back up. You may have to put up with the retrace lines though.

You can try rejuvenating the CRT, but it usually doesnt last.
dohclude



Joined: 13 Jul 2009
Posts: 5

PostPosted: Tue Jul 14, 2009 9:41 am    Post subject: Reply with quote

so it's basically trash then?
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kuhurdler



Joined: 28 Dec 2006
Posts: 2651
Location: Overland Park, KS

PostPosted: Tue Jul 14, 2009 9:58 am    Post subject: Reply with quote

that's where most of these end up.
dohclude



Joined: 13 Jul 2009
Posts: 5

PostPosted: Wed Jul 15, 2009 9:42 am    Post subject: Reply with quote

ok, well I took some pictures of the set. This thing is full of dust.

Here is the flyback (covered in a nice layer of dust lol):



and here is the "A Board":




as you can see it is slightly warped and the pins on the far right plug seem to be pulled out a little bit, probably not making a connection all the way across anymore. Is it possible that this could have something to do with my problem?

I just want to be sure it's not the crt gone bad before I throw it away. Should I try taking out all of the boards one by one and cleaning them up and checking components and maybe trying to fixed the warped "A Board" and the semi connected plug?
ntehicks



Joined: 25 Mar 2009
Posts: 162
Location: Herriman, Utah

PostPosted: Wed Jul 15, 2009 10:52 am    Post subject: Parts Reply with quote

you could sell the power supply or the main A board on Craigslist..
dohclude



Joined: 13 Jul 2009
Posts: 5

PostPosted: Wed Jul 15, 2009 1:44 pm    Post subject: Reply with quote

well, I discharged the tube, took all the boards out and dusted them off. I checked the soldering on the flyback and there appeared to be a couple of dry joints. I resoldered all of the pins to the flyback and put everything back together. I also fixed the half out plug on the main board. Now when I turn on the set, it blinks about 10 - 15 times or so then it comes on and shows a picture... but blinks back on and off ever second or two. I tried adjusting th G2 knob down just a tiny bit and it seems like the intervals are further apart when I adjust it down. If I go a down a little but more it just stays off.

I pressed the setup button on the front and the menu comes up, but it's gone again every time it blinks off and on again. this is my final attempt with this hunk of junk. So does this sound like a common symptons for a bad crt or possibly something else now?
kuhurdler



Joined: 28 Dec 2006
Posts: 2651
Location: Overland Park, KS

PostPosted: Thu Jul 16, 2009 7:36 am    Post subject: Reply with quote

still sounds like a bad CRT.

you can find tips on the 'net to bypass the IK blanking, but you won't like the results. I've done it, and it really does look like crap.
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