This is about Old CRT Sony KV 2192M3TV. IT still works very well with good picture quality. I found one side of the screen is very light and picture of that side is shown with low-contrast. Please see the attached picture herewith. I thought this is an issue in the pincushion circuit (with JRC4558) and all points were dry –soldered. But it’s still there…can you please suggest what else should I check or what can cause this issue ?

 

You are probably on the right track, looking at H. deflection. You might also want to check G1 & G2 voltages with a scope. Similarly the power supply for the video amp could have ripple from the flyback pulse on it.

Keep looking, you will probably recognise it when you see it.

 

You are probably on the right track, looking at H. deflection. You might also want to check G1 & G2 voltages with a scope. Similarly the power supply for the video amp could have ripple from the flyback pulse on it.

Keep looking, you will probably recognise it when you see it.

Thanks Sir, can you please tell me any special components to check such as Caps, Transistors ...??

 

No, don't have any documentation, but it "feels" like a capacitor. Check the H. Deflection and gun voltages and it will probably lead you
to the problem.

Somebody with experience on your chassis might have the specific knowledge you seek and they might respond here.

 

Hi,
look any capacitor showing slightly blown or they called it freggy on the top of each capacitor.
secondly look any resistor look burned due to overheated. concentrate on the horizontal area.
checked also the flyback transformer if any leak of broken shield.

 

this is the Service Manual

 

Hi,
Please look C -Board C-2 A-2/6PIN white. pin6-heater2
pin5-heater1
pin4-nc
pin3-e/gnd
pin4-200vdc
pin5-1000vdc.

measure the voltages given here. and all filter capacitor try to replaced all a new one.
its look like weak high voltage on the crt (10kv-15kv)cap. USE high voltage tester here to measure it.

 

I would say its the line scan circuit, its giving a white band on the left side( starting scan) yet displays the channel number ok on the right side.

 

Hi,
Please look C -Board C-2 A-2/6PIN white. pin6-heater2
pin5-heater1
pin4-nc
pin3-e/gnd
pin4-200vdc
pin5-1000vdc.

measure the voltages given here. and all filter capacitor try to replaced all a new one.
its look like weak high voltage on the crt (10kv-15kv)cap. USE high voltage tester here to measure it.

Thanks for the information, this is the CRT-Neck card circuit, isn't it ? other than this should we check around the FBT ???

 

I would say its the line scan circuit, its giving a white band on the left side( starting scan) yet displays the channel number ok on the right side.

can you please explain what need to be checked? where is the line scan circuit ?

 

The horizontal sweep circuit (also called the line scan circuit) is mostly to the right of Q802 middle bottom of last page. Be very careful because the are pulses of 1 kV or more in that area. Few scope probes can handle such large pulses without danger to the probe and the user.


What you would be looking for is an anomaly on the start of the horizontal scan (just after the flyback pulse) on one of the electrodes or possibly in the horizontal output circuit itself. Keep one hand in your back pocket as a precaution against electric shock.

Also keep away from the power supply, which is around T602 for the same reason -danger to your equipment and you.

 

The horizontal sweep circuit (also called the line scan circuit) is mostly to the right of Q802 middle bottom of last page. Be very careful because the are pulses of 1 kV or more in that area. Few scope probes can handle such large pulses without danger to the probe and the user.

View attachment 114936
What you would be looking for is an anomaly on the start of the horizontal scan (just after the flyback pulse) on one of the electrodes or possibly in the horizontal output circuit itself. Keep one hand in your back pocket as a precaution against electric shock.

Also keep away from the power supply, which is around T602 for the same reason -danger to your equipment and you.

Thanks ! i'll check it. by the way, this lines are verticals (see the pic pls) ...so is the horizontal scan section responsible for it ?

 

Ideally you need a Test card image to display, like this site....


http://www.stevelarkins.freeuk.com/mobile/tvtools.htm#TV_Test_Card_Download

 

Further, can this be a issue of the CRT tube socket on the Neck card ???

 

No, its a line scan fault, not the tube base...

 

Check C851 22Uf 250V on the 200V dc feed for the video amps, the cap is on the main board. Preferably just replace it as its the filter cap for the video amps on the neck card.

 

Check C851 22Uf 250V on the 200V dc feed for the video amps, the cap is on the main board. Preferably just replace it as its the filter cap for the video amps on the neck card.

Thanks for the reply. do these kind of reasons cause bright white lines only on one side of the CRT ?

 

I seem to remember that the damper circuit can cause symptoms like this. Do others agree?

 

I seem to remember that the damper circuit can cause symptoms like this. Do others agree?

Thanks for the reply, what parts of the damper circuit should i check according to the attached circuit diagram ?

 

I have fixed this kinda issues long time ago.
I remember replacing some capacitors. Some times on the neck board and some times around the FBT.
This problem is caused by leaky electrolytic.