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TV DAEWOO MODEL DTH-21S7 DOES NOT TURN ON

Afner
Afner
16
hace 5 años
hace 5 años
Hello friends of the forum, my greeting resides after a while I was away, but we are again. Now I need your help. I have a TV of the brand DAEWOO model DTH-21S7 chassis CM-111S, which was the damaged source and when repairing it the voltages are fine. In the + B I have 134v. In the other outputs I have 50v., 6.5v, and 12v but when I give it power the TV activates the relax and it is deactivated, and when measuring the voltages they go down to zero. Then and disconnected the vertical IC LA78040 and also disconnect the jomper that drives the voltage of + B and I used a 60w bulb and the normal TV does not turn off and the vertical line comes out on the screen and when welding the vertical integrated returns to the same, then change the integrated and nothing of good result, also changed capacitors around the integrated and does not turn on. For this reason I want your help. Fat in advance
internetciano
hace 5 años

How about Afner, verify that the correct voltage is coming to the vertical integrated, usually this is fed with a voltage from the flyback, make a follow-up to that voltage since leaving the flyback (checking diodes, capacitors, that are not in short or open) until you reach the integrated power supply pin (s), also check the components that connect to the vertical coil. Here is the service manual:
https://elektrotanya.com/daewoo_dth-21s7_dth-21s8_chassis_cm-101s_sm.pdf/download.html

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Afner
Afner
16
hace 5 años

Fat friend already check the diagram but it does not apply as I have this tv, in microprocessor it is floor and the voltages of the flyback for the vertical is +14 and - 14. In the output for the video is 190v. Check and continue with the same, more help xfa

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internetciano
hace 5 años

Ok, look in the mainboard screen printing for the chassis number to look for the diagram, when you mean "floor" is it because it is surface mounted? Try turning on the TV with the integrated one in place, but you take the power off; in the line of the + 14 / -14volt that come out of the flyback, lift each end of the rectifying diodes (the +14 and -14) to remove the power to the vertical. The TV should turn on with a horizontal stripe on the screen, if you turn on the fault you must have it between the power line and the vertical integrated and / or its components

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Afner
Afner
16
hace 5 años

I have also made it my friend and I have no results, as for the integrated one that I tell you if it is stuck on the board, it is not like the other microprocessors, which would be the other idea and also the chassis number is the one that I sent you CM-111s

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manolo karvalo
hace 5 años

friend. measure the tension on each pin of the ic Vertical and upload results so that the pin is missing.

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manolo karvalo
hace 5 años
hace 5 años
Hello Friend. if you changed the filters for new ones that are related to the ic. la78040 you must also change the diode even if it measures the one that feeds the ic. vertical. and check the resistors that feed the diode. Cheers
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