How To Locate The Primary Winding Of Flyback Transformer

By Jestine Yong on November 24, 2008

flyback schematic

Got a question from ERG member:

Can the Blue Ring Tester that I purchased from you be able to test the TV Flyback Transformers?

Jestine- Yes you can
And what If I do not have some of the TV schematic diagrams, how should I identify which pins in pair. Meaning to say pin No.? & pin No.? are related for testing.

Jestine- Check for the flyback pin that goes to the collector pin of HOT and the B+ pin (supply from power supply). That is the primary winding of flyback transformer.

If you are repairing the CRT Monitor then you have to find out from center pin of the B+ FET that goes through a Diode (ultra fast recovery diode) and then to the flyback pin. Another pin was from the collector of HOT. Both the pins is the primary winding of the flyback transformer. Try practice to find these two pins because i came across quite a number of technicians could not trace these pins. The primary winding is important if you are in the CRT TV/Monitor repair because a shorted/ partial shorted winding could cause the equipment to shutdown, low power, power blink or even blow up the HOT. If you come across a shorted HOT please make sure you test this primary winding before you put in a new HOT otherwise if the primary winding have problem, it may takes a split of seconds to kill the new HOT.

Again, it come back to the important of using flyback tester/Blue Ring Tester to find out the bad winding. Without the tester, surely it would take you a longer time to troubleshoot the problem that related to shorted primary winding in Flyback transformer.

8 Comments

russ

February 22, 2011 at 5:09 am

If I don’t have a schematic how do I know where the B plus is? Are there some more clues you can give? Are they ever at the same pin number, or do they ever read a particular ohm? Can you show me some exambles on a flyback and on a schematic?
Thank you
Russ

Reply
admin

February 22, 2011 at 8:44 am

HI Russ,

For a TV, just trace the 110 vdc line of the power supply and it will lead you to the B+ pin of flyback.

Jestine

Reply
lito mendoza

September 28, 2011 at 8:42 am

jestine,

aside from the 2 pins of the primary winding in the lopt/fbt transformers, what are the functions of the remaining pins? just in case the primary winding of lopt/fbt is ok, will the remaining pins of the transformers be the cause of the tv/monitor shutting down?

thanks a lot,

lito

Reply
admin

September 29, 2011 at 8:39 am

Hi Lito,

Try this link:

http://electronicrepairguide.com/flyback-transformer-pinout.html.

usually the secaondary winding will not cause shutdown unless it is shorted.

Jestine

Reply
worku

October 17, 2011 at 9:32 am

how to check the fly back ,it is normal or not normal

Reply
admin

October 18, 2011 at 3:25 am

HI Worku,

Try this link:

http://www.electronicrepairguide.com/testing-flyback-transformer.html

Jestine

Reply
jojogreg

September 5, 2012 at 11:11 pm

hi jestine,
Can i measure the primary winding of the flyback transformer using analog or digital multimeter?How can i know that the primary winding is defective?Is it shorted or a zero resistance?What is the right range setting in the analog meter if possible..

Reply
- Jestine Yong
  
  September 6, 2012 at 3:47 am
  
  Hi JOJO,
  
  You can’t use analog/digital meter to check on the primary winding because a shorted winding the meter will still show good reading (Ohms value). You need Blue Ring Tester to locate shorted winding in flyback transformer.
  
  Jestine
  
  Reply