Dear Moderators,
My 8 year old TV suddenly came to a halt and the s/by light blinks twice per interval when I try to switch it on with my Rmt Ctl. The Horizontal Output Transistor D 2578 had all its pins shorted. I changed it but still light blinks twice ( I did not prolong TV switched on should the 'HOT' busts again! ) I then checked the rectifiers and resistors randomly but could not find the fault. There is no service manual or schematic diagram with me hence difficulty tracing the fault. ( I hope some nice people out there can help me with a download copy ). I understand from the forum that there is a resistor 'open' - which one? Are any other components fault the probable cause? Please help. Thanks. Maha.
KV-XG29M blinks twice - PROBLEM SOLVED.
Armed with a fair amount of information from TV faults forums, I went ahead determined to get it over with - as follows:-
1. Obtained service manual and schematic fron the internet. If you are persistent, you will find it - FOC.
2. The HOT (Horizontal Output Transistor) Q511 (2SD 2578-CA) had all its pins shorted.
3. Bought a non-genuine part for 5 Ringgit Malaysia (US1.20) and after replacing - still 2 blinks.
4. Checked further focusing on short circuits in the power transistors, IC Vcc to Ground and power resistors on the D Main Board.
5. R615 (1 ohm 2W) Metal Oxide which supplies 33.7volts to collector of Q604 was open. Replaced with the same metal oxide type US0.25 - result still two blinks.( At this point, I was looking for the nearest Sony service center!!)
6. Read and read every information on the net and seeked help from Techchris (www.tv-forums.com.) He replied - 'remove the HOT and check the voltage at the collector pin - if it shows around 120 volt, than the FBT (Flyback transormer) is likely to be faulty'. It measured 125Volt!I was truly not happy as I know Sony FBT costs hell. Non-genuine cheapo components will not last long on Sonys'.
7. As I was removing the connectors on the D board so that I could desolder the FBT pins - I FOUND THE PROBLEM!!.
8. The spade connector beside the FBT from pin 14 of the FBT was wobbly (loose).this connector carries a black wire to the Deflection board D1 at the CRT (Picture Tube) neck.
9. Checking the continuity from spade connector to FBT pin 14 with a multimeter showed an open circuit.
10. On further check, found the layer of solder at the spade base was so thin - causing the loose connection. I cut a small piece of double-insulated multistrand wire and soldered between pin 14 and spade base connector.
11. Aha! the TV is up and running. I quickly replaced the cheapo HOT with a genuine Sony part (US5.50).
12.Apparently a loose joint at any horizontal circuit area will cause damage to the other components.New components will blow as long as the actual fault is still there. I then went about to desolder and resolder all the heat joints after scraping the component pins.
13. My best warmest regards to all those fine people who had contributed in one way or other for my success.
14. The satisfaction one gets in bringing a dead TV back to life is so great. THANKS. [email protected]
I've been repairing all sorts of tv problem for years and found it rather easier to find the fault, but not this sony XG29M50. When switched on the tv,sound coming out but then back to st/by for 3-5 sec and blink twice. Can anybody out there please help me to solve this problem.tq!
Hi Henry, the problem mostly with a sony is a dry solder joint somewhere either at the power supply board or the main board where the Horizontal Output transistor is placed. In all cases, this weak solder joint shorts the power output resulting in the two times blink. In your case yes! the audio is OK thats why you hear the sound briefly. But the TV is switching off to save your set from further damage.
2. A weak solder joint is the hardest problem to find in a TV - take your time and check piece by piece (with a magnifying glass and continuity check)as per my direction above. Surely you will eventually find the problem. My Sony is still going fine into the 9th year.
Best of Luck - rgrds Maha.