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Re: Picture too wide
This is usually caused by failing capacitors in the pin amp section. Testing caps with an ESR meter is a good way to find the failed caps. Or, you can do it by replacing the caps by guessing. Or, you can use a scope and follow up for the proper waveforms.
While you are working on the set, it would be best to verify the caps in the power supply and scan amplifiers.
If the fault is more complicated than just caps, you will probably require the service manual and have to spend the time to troublshoot the pin amp circuits.
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Check its "Pin-cushion" section circuit for the fault. An IC is used there to control the pin cushion distortion. If this IC has got faulty, this type of fault can occur. This is actually a skilled work. If you are not ahndy, seek any technicians' support.
Could be something as simple as a bad contact on one of the deflection yokes or other coils on the cathode ray tube - check the contacts on the circuit board where these coils are connected, resolder the pins or wires if the contact is bad, also check connector pins for any dirt or oxydation and clean if necessary.
This is a vertical circuit problem that is either bad connections on the vertical IC or a defective IC. If you can solder, you can fix this yourself. Look for a small flat IC attached to a heatsink with about 9-11 pins. It may be marked LA7837 or something similar. Try resoldering the pins first. If that fails to resolve the problem, replace the IC. There may be defective caps in the circuit as well, but those don't usually cause complete vertical failure. If the picture does not return fully, update this and we'll continue on to the next step.
This trouble symptom picture wide or"blooming", the picture becomes dim even with the brightness control full on,and there is an abnormal enlargement of picture or raster.Usually,the enlargement is uniform,but there may be some defocusing.In some circuits,the brightness control operatesin reverse(rotating the control for an increase in brightness produces a decrease) after reaching a critical point on the control. If the picture wide is not accompanied by insufficient width(a symptom of horizontal output failure) the probable cause is a high volatge circuit ony,particularly the HV rectifier and HV winding.Any circuit problem that reduces but does not completely eliminate the high-voltage output to the picture tube second anode can cause overscan. The most likely defects are leaking high-voltage capacitors,defective high voltge tube rectifiers,leaking high voltage leads,defects in high voltage circuit protective resistance,and shorted turns in high voltage winding of the flyback transformer.
I cannot tell you locations for parts in this model, but this fault is genericaly very much the same for all CRT sets.
There is a fault in the pin cushoning circuits. Usually this is from failing electrolytic caps in that area. The pin amp is also part of the vert and horiz deflection circuits. Sometimes the pin amp driver devices (IC's or transistors) can also be at fault.
With an ESR meter it is very easy to find the defective caps. They will have higher than normal ESR than the caps that are working properly.
If the barrel distortion is along the width of the display, this indicates that the pin fault is in the vertical pinn part of the pinn circuits.
This is a pin cushoning fault. The failure is in the pin amp, and also most likely in the scan amplifier sections. The scan amps and pin amp in part of their functions work together to control the paralax of the picture scanning. They also control the dynamic focus.
To service this, you will need the training, service information, the testing tools, parts availability, and the necessary tools to follow up.
These types of faults can be complex to service, and can be a chalenge to even an experienced tech.