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HomeProblems with the power supply I had, as many of you, the common power supply problem with my Sony KV27TS29. I replaced the Q601 and Q602 (Twin Transistors C4834, the R607 (0.1 ohm Fusible Resistor)and the transistor C4927. It worked well for a couple of hours and after that I noticed a shrinking band on the right side of the screen, which disappeared after a while and came back one more time. After a few minutes, the TV went black again, no sound no picture and I suspect I'll have to repeat the same operation. Is it the flyback transformer? An electrolytic capacitor? Is there anyone among you who could tell me what else I should change to eliminate that shrinkage? Your help would be greatly appreciated. Thanks!
6 comments
que tal colega te comento que aparte de cambiar los componentes de la fuente,tambien cambies los reguladores de 12v y 9v.,asi te parescan en buen estado.coloca componentes originales en lo posible.suerte. I have a KV27TS29 set that had a power supply problem and it cost $300 to fix it. It went out again (and me being an electrical engineer for 35 years)and said it can't be that tough. The guys that designed this set had a pact with the Devil. To make a long story short: 1) You will never get anywhere without a set of schematics...or you are just lucky. SAM'S photofact has a package on line for $21. An O scope will help a lot. 2) Q601 and Q602 always short if the fuseable link R607 is open. 3) These transistors may be replaced with ST13009 from Digikey for $1.50 each. These have copper heat sinks and a thermal isolator kit is also required, but they are faster, higher wattage and higher voltage than the Sony part (if you can find them). R607 may be replaced with a WLAR010FECT-ND resistor. 4) After replacing these 3 parts, place a 40W light bulb in series with the TV power cord. This will protect the switcher by limiting the line current while it runs in the low power mode. (TV power on switch should be in OFF). 5) At first plug in, the bulb will be bright for a second or two then either: Glow Orange===> Set is drawing too much power and something else is wrong. The switching transformer requires a minimum load to operate correctly of there could be excessive load somewhere in the Standby circuits. Lamp goes out===> Says switcher Q6101 & Q602 is operating OK and that problem will probably show up when power switch is turned to ON. 6) Even if set is OK, the light bulb will flash white and decay to glow as set tries to start. 7) At that point you have to remove the light bulb from the circuit and hope for the best. Good Luck I did replace both of them, the twin transistor and de H output, they burnt all again, then, I are thinking that de silicone heat sink grease is missing, you could check this too. I'm not replace the transistor yet until i get the grease. Bye Jorge q591,q601 ,q602, and r607 went bad.what could be the problem? I have the same problem did you had any help, I will appretiate an awnser or if you have the schematic it will help thanks. kam i fixed trukloads of these. look for cold solder joints on the secondary winding of the HDT transformer. and H out to. these were money makers..... |
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