Tip & How-To about Televison & Video
You try to turn on you Sony TV and nothing seems to happen. Then you notice the standby/power lamp is blinking. Counting the blinks during the short versus long pause reveals that the unit is blinking 6 times, pausing for 3 seconds then blinking 6 times. This continues as long as the unit has power.
What does this mean? It means that you have a serious problem in the horizontal drive circuit. The horizontal circuit provides the high voltage (38kv or higher) to drive the electron beam to the front of the CRT and the phosphors.
This diagnostic tool is there to help you narrow down the area of the problem. For this blink sequence you need to look in the vicinity of the flyback transformer. It is the large, round or squarish, device, near the rear of the set. In Sony's it is almost always on the right rear corner of the set. You can recognize it by the large red rubber wires (four total) coming from the unit. One is unput, three are outputs and go to a focus divider block or more recently to the CRTs.
The flyback takes about 1000 volts ac and raises it to over 38 thousand volts dc. This is done by have a few turns of wire on the primary of the transformer and many turns on the secondary. This is determined at the factory and sets the level of the voltage. TVs use a pulse at 17750 khz/sec to create the stepup voltage. This is provided by circuitry which includes a switching transistor or IC.
The switching device must control a small current/high voltage but gets very hot because of the high frequency that it runs at. Many times the horizontal output transistor is blown. When replacing the HOT always replace the flyback as more than likely it is shorted or partially shorted and will just blow a new HOT immediately or within a week.
If you can use a DMM and know how to test transistors you can check this. It will be near the flyback and mounted to a large aluminum heat sink.
I have a tip at http://www.fixya.com/support/r4916941-diagnose_repair_projection_tv_high which will help walk you through it and also tell you where to get the parts at the best price.
If you do not have the experience you may want to consider just replacing the entire board. Prices have come down quite a bit and there are aftermarket repair facilities which will repair the board as good or better than new and have the same or better warranty as a new board. I have a tip at http://www.fixya.com/support/r6981868-replace_circuit_board_in_modern_tvs which will give you tips and the know how to accomplish the board swap and also the best places to get the new board.
If you have troubleshooting skills and want to try to fix the unit yourself, check the HOT, Flyback, C515, C516 and the jungle IC, IC206. For this kind of repair you will need a service manual. http://encompass.com has many posted on their site, but not everyone. http://servicemanuals.net has all service manuals and you can download most for around $16.00 USD.
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Posted by Kim... on
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