Sound perfect but no picture replaced faulty line output transist
Philips projection colour tv chassis GFL 7D line output transistor Q906 was replaced but to noavail. checked voltage 130vC disappears on collector of Q906 when you disconnect the line leading to diodeD918 before collector of line output transistor ,you get the voltage.Kinndly advice what to do and how to check the line output stage up to the H V Splitter and the three RH v,GH v and BH v
Regards and God bless you Guy Sillwamba
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Your TVs red colour output section has the trouble. There is no red output at the red cathode of the picture tube. The red, green, and blue output sections are on the picture tube base board. In some Philips model, these will be consists of transistors, and some has an IC or Tree ICs for three colour output used. You just open your TV, measure the voltages at these three cahodes. There will be markings on the printed circuit board for these cathodes marked as [Rk,Bk and Gk].
In your TVs case the voltage at the Rk marked pin will be higher that the other two cathodes. This can be caused by an open drive transistor or an Ic whichever may ysed there. If it is transistor, just replace it with a same type and number, as in the ace of ICs the related Ic, must be replaced. If only one Ic is uded for red, green and blue outputs, that Ic must be replaced.
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Your TVs video output transistor [Red] has got shorted. Usually a transistors are used in most of the colour telivisions in video output stage.. If it is a transistorised video output stage, replacing red output transistor will solve the problem. In some modern sets there are so many types of Integrated Circuts [ICs] are used. If your TV uses Ic as video output, replace the Ic.
It sounds like a fault on the line output stage, but to be perfectly honest I have never seen inside a projection tv so I can only guess a faulty line output transformer or line output transistor. If not it could be some of the related components on the line output stage. Hope this helps.
The chirping sound indicates the power supply is starting finding a problem and shutting down hence the cycling trip can be caused by any number of faults but I would first try the Line output transistor for a short collector to chassis if this is ok then Philips TV are prone to the small blue high voltage capacitors (2/3 Kv.102k/222k) becoming short usually indicated by being burnt or very discoloured.. If you are not technically minded its best left to a Tech.. Hope this helps.SUPER8
There is a fault on the line output stage either dry solder joints on then transformer or relating components or the line output transformer or transistor is faulty and needs replacing. Hope this helps.
That TV uses the PTK195 chassis, and the fact that you see only a thin line for each color near the bottom of the screen tells me your vertical output IC has stopped working, and is putting a small DC voltage across the yokes. I have seen this caused by a defective vertical output IC and I have also seen vertical problems caused by a small CRT coolant leak which drips onto the main board near the vertical output IC. If you do not have experience servicing the PTK195 chassis than have a qualified tech handle it for you.
this could be caused by 1 of 2 things, firstly the crt could be arcing, check this by taking the tube base away from the tube neck (only do this if you are a qualified engineer, high voltage and all that), secondly your F.B.T. (Fly-Back Transformer) could be up the swanny (faulty).
It would be handy to know if the transistor blows instantly.
Hope this is of some help to you,
please email me if you require anymore assistance