Sony KV J29 Green Lines

Sorry, forgot to mention that the audio and video is perfectly fine. These green lines appear on the picture and not very very bright but visible and is irritating.

sounds like bad caps to me.

yes, they are very thin and slant slight downward correct?

quoted text -

right... but how do i figure out the bad cap's ? if it was a retrace path problem, i should be seeing white lines... how do u explain the green lines ?

There are several things that can cause your fault. It may be a failure in the blanking circuits, or the picture tube is going defective. Take the TV for a service estimate. This is not something you will be able to service yourself without the proper training, tools, and service information. It will involve troubleshooting, ordering parts, and possibly doing some adjustments. If the fault is the tube, then the set will not be worth to service.

Jerry G. =====

Do you ever contribute anything useful to the group? All I ever see are canned responses telling people to take things in for service. Yes in many cases that's the best solution, but much of the time the stuff is not worth paying to have serviced and someone may as well take a shot at it. Don't be so quick to assume people are incompetent even if most of them are.

Do you have access to an oscilloscope and the schematic for the set??

H. R. (Bob) Hofmann

James Thanks for your suggestion. Of course going to the technician is choice, but my approach towards this is a bit of learning, rekindle my electronics enthusiasm and also have enough knowledge about the fault so that the technician does not fool me by robbing a moolah and just replace a resistor/capacitor. I am sure you would encourage people learn things.

Hoffmann I dont have access to the oscilloscope or schematic of the set. Is there any way, I could download the service manual and schematc of this set... do you guys know of some good free websites that provide tips of Sony TV repair ?

All I have a slight correction to the problem. I went very very close to the TV and realised that the lines are not green but white color. I dont know why they appeared green to me from distance... anyways. I counted them. They are about 22 in total spread over the screen. The distance between the bottom two is about my two fingers and gradually the distance between lines starts to decrease with the topmost having lesser than my index finger. They are slanted upwards towards right , yes upwards !! and NOT downwards. The bottom most line kind of starts from the centre of the screen. Most of the lines are the centre of the screen do not touch the leftmost and right most edges giving the whole pattern kind of a fat hour glass look.

Now since these are white colour , i suspect these may be got to do with the vertical flyback blanking system.

You shouldn't need either, I've been repairing things as a hobby for years, I have a scope but rarely use it for repair, and schematics, those come once in a blue moon, but usually it's just old fashioned intuition and a multimeter. Look for a shorted transistor in the green drive circuit, probably not the one directly connected to the green cathode or the whole picture would have a green haze to it, but look further down the line, closer to the video processing section.

Today, I opened the TV. Here are some of my experiements

I could locate the G2 pot on the PBC on the screen neck. I tried to vary the G2 and clockwise movement helped to make these lines a bit more lighter but then the TV takes about 1 minute to show the picture whereas sound comes out immediately. I did some trial and error and have kept the setting that reduces the lines a bit but takes about 30 to 45 sec for the picture to appear on the screen.

Can someon help me with the schematic and service manual ? I dont know how to find the chassis number, but this is what I could read on all the boards

There is a sticker on the CRT that says KV-29JMN1AK SCC-K67PA CHA NO

There is a rectangular board that says F2 Sony 1-670-752-12 F2601 T4.0A250V

The largest mother board has following written on it 1-666-699-21 There is a very large "A" printed on the board

The PCB on the neck of the CRT has following NE M PF2 1-656-470-15 (1-710-283-15)

My email is snipped-for-privacy@gmail.com

Trace out the green video amp, try disconnecting the wire carrying the green video from the main board to the neck board by removing the solder from the pin and see if the green lines dissappear. If you can narrow down which board the problem is on, you'll make things easier.

Sure I will do this. Another thing I noticed. About an year back, this TV had developed a problem. The sony technician said he would do direct connection of the CRT tube. I see that he has taken a simple wire with insulation, wound about 4 to 5 turns around the Flyback arm. One wire end is soldered to the H pin ( I think it was H-) on the CRT neck board. This H pin is one of the 13pins that hook into the CRT.....and other wire is soldered to a resistor very near to the H- pin. one end of the resistor is on the board and the other end is removed and connected to this wire. Not sure what this arrangement was for....

I know, the above is more english and less technical, but thats all i could see there.... can anyone pls help me to understand what the technician tried to do here ?

After 6 months of the above repair, the TV again developed problems where there are no green colour. He changed the IC8575A and it worked perfectly. ( I brought a new IC from market, placed it myself, but the problem did not solve. The technician then took away the board, removed my new IC and he put another IC and according to him, the problem was solved... but i am not ready to believe him... when I soldered my new IC, i had put a IC base,,, but this guy removed my IC base and solved his IC back on the board.... somehow I feel that my original IC was good and there was some resistor/capacitor faulty in the path... :-)

He's isolated the heater, suspecting a heater to cathode short inside the electron gun. It's quite possible that your problem is in fact a faulty picture tube.