Question about Sony KV-36FV26 TV
Hello: I was wondering if someone can help me or shed some light on my problem. I've got a sony wega kv-36fv26 for about 7 years now, everything is great on it; but, I've noticed that the last 3 years of so, there is a high pitched humming sound comming for the back of the tube (kinda like a high pitched whistle sound), strangely this only occurs in the hot summer months, I'm assuming it has something to do with humidity in the air. Awhile back just before the warranty expired I had call for a repair and the tech had sprayed some sort of silicone around the yoke, it help for about a year or two and now it's back. My question is does anyone know what kind of spray this is and secondly is there as solution to my problem. Thanks
Hi there, I'll start out by saying that I am a T.V. engineer (now retired). If the problem is exactly as before when the repair guy fixed it for you it is going to be due as you quite rightly say to humidity. A cathode ray tube (CRT) requires a very high voltage (EHT) which can be in the range of 18-30 thousand volts (18-30KV) This voltage is derived from the line output stage of the television and is fed to the tube by means of a single wire terminated with a single connection with shroud. It is usual at this connection to find dust and humidity causing a problem. It is really best to disconnect from the CRT and clean the insulating shroud and the glass area out to the graphite coating of the tube. WD40 will do just fine and a smear of silicone grease after cleaning delays the time span until the next time you need to do it ,although not strictly necessary. WARNING !!! Even with the T.V disconnected from the mains supply the CRT acts as a big capacitor and hold a charge of several thousand volts. It is necessary to discharge this with a couple of insulated screwdivers from the connection point to the graphite coating if you do not want to experience something like a stun gun shock !! If you are not happy about doing this - call someone in. Another reason for high pitched whistles can be loose laminations (coil windings) on the line output transformer which works at a very high frequency. Changing the transformer is usually the only answer in that sort of scenario. Hope the answer is of some help. Be careful with electrics. Regards. Mike.
Posted on Jul 27, 2007
Remove the yoke and DISCHARGE the tube completely then clean with some kind of alcohol based product. get some patrolium gel not vasileen and fill the EHT hole with it and smeer it about an inch or so on the tube and inside the EHT cap this will seal the cap.the reason for the whistle is that carona is leaking and loading the line timebase and will eventually cause the line time base to fail don,t forget you must discharge the tube if you don,t want to get 20'000 plus volts dc up your ass.hope this is successful .
Posted on Jul 27, 2007
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