Set came in with usual high voltage snapping at anode replaced anode cap and wire and silicone set then fired up ok but with poor luminance , looks like problem where raster is similar to turning up screen control this was a common fault on older rca sets it was caused by a shorted buffer transistor. can not seem to isolate this one, i have a schematic on order,have checked all caps,coils and resistors in video area even changed out t-chip any one have a solution thanks tutt.
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This type of noise usually comes from a CRT based tv will be from its EHT cap. EHT cap is one which connected to the top of the p[icture tube, through which the extra high tesion voltage is supplied to it from the line output transformer. Normally there will be a smell of Ozone gas from the back side of the TV. Eht cap is a silicon rubber boot that protects the inner high tension voltage from being come to contact with open air. Due some reasons, if this rubber cap has some trouble; the extra high tension DC voltage supplied to the CRT [it usually come up to 32KVDC [32,000 VDC] will happen in contact with the open air, and if the humidity in air also is great, arcing will take place, converting Oxygen in the air to get converted to Ozone. If you look through the ventilation holes of the TV, in absolute darkness, you can see a bluish glow there aroung this anode cap. In some cases, this rubber cap can be replaced with a new one if available. if it is not available, you have to replace the line output transformer; otherwise called as [LOT]. This anode spot is a dagerous one for an unexperienced person to handle. because charged voltage will be there for a long time after switch OFF the TV.
It is best to contact an expereinced service person to get it repaired. OK.
good day since you have been already replaced the fly back transformer as you said so meaning the problem is not the FBT. any way here are some of my recommendation to isolate the problem .
unplug the tv unit and then unscrew to open the back cover and gain access the crt chassis.
now with use of flat screw driver remove the anode cap of fly back transformer make sure you discharge first for your safety.how are you going to discharge the voltage,get single wire then flat screw driver now strip one end of the wire and tie it to the flat screw driver the other end of the wire splice at the chassis ground of picture tube. and then insert the end portion of the flat screw driver to the anode cap to discharge the voltage left. you can now pull out the anode cap.
by this time you will turn on the tv unit place the anode cap in a safe position not to damage the board be careful its a high voltage. plug the power cord and turn on then observed if their is an arching at the anode cap usually a blue color just to know if the high voltage is present.
if their is a high voltage that means horizontal output transistor is good thats why the fly back transformer is on. your next step is to check the secondary voltage of fly back transformer with the use of digital tester or even an analog tester to know why their is no 1000v. check bad fusible resistor near the fly back transformer usually a 22ohms value this is where the 1000v pass through going to chroma board or video board. if open or no resistance pull out the said part and then replace with the same rating value.check also shorted diode connected to the resistor sometimes it was the cause why the resistor get bad.
after you replaced defective part insert again the anode cap for testing once again be careful.
now turn on again the tv unit then observed if their is a video on the screen check also the heater voltage at the chroma board if present usually about 2Vac something you will also noticed their is a light at the neck of the picture tube.
if the 1000V is present the heater and the B+ supply voltage i'm sure the video will come out. i hope those steps that i give to you will help to fix your problem thanks for choosing the fixya if you have further question i'm glad to help you.
Your TV is actually functioning but their is probably a leakage on high voltage supply. Warning : The next procedure should be done by an expert. 1.Clean the anode cap mounted on the CRT.But before touching the cap be sure that the voltage stored in the CRT is discharge to avoid risk of electric shock.It is done by creating a path of conduction from anode cap to chassis ground. 2.After cleaning the anode cap and the CRT surface.Attached the anode cap to the CRT.Be sure after attaching the pins correctly push and vacuum the socket and the cap to seal leakage.
Normally an arc or snap like that is coming from the anode cap that attaches to the top center of the crt. The voltage there is upwards of 25k so be VERY careful if you're going to inspect this for any faults. If it is the cap leaking unplug the set and take a piece of wire attached to a screw driver with the other end of the wire attached to the grounding cable around the outer edge of the crt. Gently undo the cap from the crt and allow the blade to sit in the well for a period of time to discharge the crt completely.
Next get some HV putty, sold at most electronics distributors like Mouser and form a small ring with it. Place it around the well hole in the crt and replace the anode cap pressing firmly to seal the edges of the cap to the crt. With the back still off plug the unit in and see if that's cured the problem.
that sound is comming from the tube anode it is leaking you have to discharge the high voltage from the anode cap,then take off the cap clean the area with alcohol and put some red or clear silicone on the cap and anode connection replace back the cap on the tube leave to dry for about half hour,this will remedy your problem,no more static.good luck.
most high pitch noise comes from the anode conection on the picture tube thats connected to the flyback anode cap thats mean there is a high voltage leak,to stop the noise you can discharge the high voltage take off the cap and clean with alcohol.if the noise continue.you will have to put some red or clear silicone both the cap and tube stick together leave to dry for about 2 to 4 hrs.this will eliminate the leaking.good luck.
The anode cap on the back of the tv tube is leaking the high voltage be careful as going into the back of a tv it store very high voltage and could be fatal.the solution to problem get a tube of clear or red silicone discharge the high from the tube,you do this by getting a alligator clip with wire attach clip to a ground wire on the back of the tube attached the other end of the wire to screw driver gently push it under the Anode cap you will hear a popping sound with i little sparks. remove the cap from off the tube get some alcohol wipe the dirt away apply the silicone around the anode and the anode cap place in on back and leave it to dry and cure for about 7 hrs close up back and turn on your tv and all the popping sound is gone.good luck.but if it is the wire for the anode cap that comes from the flyback is the one leaking change the flyback.again good luck.contact me on fixya.com or email me at [email protected]