Wednesday, June 18, 2014

CRT Television secondary output supply query



Hi Humphrey,
I just bought your book several days ago and right now i was reading it. Can you please help me; there are things i can not understand in chapter 6 specially the B1 to B6.

 I cant find them in the schematic diagram. Do you have schematic that has a label B1 until B6 for chapter 6?

I am so excited about this book, you see, i took a lesson from a technical school But I already forgot.

With this book, I will have something to refer to anytime I Want. After this book, i plan to also buy book from you like LCD and Plasma TV
REPAIR.

Thanks a lot.

Edu Vejano

Philippines

Hi Edu,

Thanks for your feedback and glad to hear from you,

Back to your question, as you have noticed in this chapter I am explaining about the secondary outputs in s.m.p.s.

All switch mode power supplies usually has a number of outputs which varies depending on the model but the minimum is two.

When the outputs are two, one will be high voltage over 100Volts and the other is low voltage around 20 volts.

In this case you can assume the high voltage is the B+ (B1) and the lower voltage is B2.

This I used just for education purposes and therefore it is not labeled but in some models they label the B+ voltage which supplies the fly- back transformer.

In absence of a circuit diagram you can figure out the B+ voltage by considering the working voltage of the capacitor used to filter that line which is usually rated 160Volts.

See the diagram below for more info.
 


Kind regards

Humphrey Kimathi


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