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TVs

doubt with taking voltages on flyback and undercut the yoke.

evolutionstore2009
hace 6 años
hace 6 años
Goodnight. I am a beginner of electronics and what I have learned I achieve in tutorials since where I live there are no electronics schools. I have a sanyo TV of 29 generic chassis t08-29k. The problem is that it burns the horizontal instantly. I changed capacitors of the horizontal stage and around the fñyback. Remove the fly back and take it to try. It's ok. By doing the test with the series of bulbs and without the tsh without connecting it to the screen I was still taking voltages. The doubt that I have is. All voltages measured in the fly back bone on pin 10 is written 180v. In H. ABL Y + B SON in AC. Because on pin 10 where 180V is written, the MULTIMETER frames me on alternate 210 on stand by and 290 on Power. In the yoke socket on the Pines kb.kr, Kg in ac marked equal 210 in stand by and 290 with power in ac. . What components should I review? Thanks for your opinions.
manolo karvalo
hace 6 años

Hi friend. dismantle the yoke and check if the bovines are not sulphonated or with a short signal, and check the bovine that is close to the tsh. It may be overheated. regards

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Alexis Navarro
hace 6 años
hace 6 años
Cordial greeting friend Evolution store2, the voltages that come out of the different pins of the flyback directly in their pins are alternating voltages (AC) of high frequency since they are generated by the oscillation of the horizontal circuit that activates the flyback and these should not be measured with any multimeter since it is not very common that the multimeters bring this option of high frequency, only some bring it, as you will see after the pins of the flyback come resistances low in ohmiaje as protection and after these diodes are rectifiers that there if you can measure with the multimeter in DC scale, are the 180VDC of the color transistors or those that bring an IC, are the 26VDC of the vertical, the 16VDC of video, in some they bring -16VDC, to the pin of the ABL they arrive approximately of 9 to 12VDC, these come mostly from the B + of the flyback and this comes from the source, only the filament voltage that is mostly identified as (H) 8Heater) and H gnd are voltages short of about 4 to 6 VAC that these if you can measure them directly, the rest must be measured after the diode rectifier in DC scale, in the connector of the yoke should only measure the pins that correspond to the vertical, in scale DC I do not remember very well but I think it is in DC and in the pins of the horizontal it is not recommended since it is also high frequency voltage and the voltage there is about 2KVDC if I am not bad. the multimeters do not have that capacity of mdicion unless it is with a special probe, I hope my opinion has been able to clarify your doubts Greetings.
Joansoler
Joansoler
47.894
hace 6 años
hace 6 años
[i] Let's see, the FBT (Fly Back Transformer) receives direct or continuous voltage (DC or DC) only on 2 of its pins, one is the "+ B" to feed the TSH collector or HOT, and the other is the "ABL". The other pins of the FBT deliver high frequency pulsed (non-symmetric AC) voltages (PAL: 15 625Hz / NTSC: 15 734Hz) ... ** NOTE: + B = + VCC Only in some cases where the primary winding has a "derivation" from where the "180V" pin is obtained, on this pin the measured voltage will be equal to + B and it can also be measured in DC or DC. Regards! Joansoler. [/I]
evolutionstore2009
hace 6 años

Hi. Thanks for the answers. I'm clear on what points to measure. But. The doubt that I still have is. If pin 10 of the fly back is marked with 180v. I take the voltage in the capacitor after the diode. But those 180v are alternate or dc. because the two values are different.

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Joansoler
Joansoler
47.894
hace 6 años

Let's see, all the voltages that come out of the FBT are "pulses" (not symmetric alternating current), directly they do not serve to feed other auxiliary stages of the TV, because for this DC or DC is needed (like that of a battery or battery) . That is why we find those "fast diodes" that are responsible for their "rectification" and the "capacitors" connected to their output, are responsible for their "filtering" or smoothing, then on these capacitors should always be measured in "V DC" or "V CC". If the TV does not turn on then on those capacitors there will be no tension (0).

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