Q: pins on flyback transformers

[Dominic-Luc Webb]

I was about to toss out some old computer monitors, but thought to pull
the flyback transformers for use in some of my high voltage projects.
Question: Is there some simple trick to determine which pins are which?
Maybe there is somewhere online that posts pinouts for more common
flybacks found in more common monitors and TVs?

Also, maybe someone knows some cute trick to removing them from the
circuit board? There's a lot of pins and they are soldered in pretty
securely.

Dominic

 

[Andrew Holme]

Dominic-Luc Webb wrote:

I was about to toss out some old computer monitors, but thought to
pull the flyback transformers for use in some of my high voltage
projects. Question: Is there some simple trick to determine which
pins are which? Maybe there is somewhere online that posts pinouts
for more common flybacks found in more common monitors and TVs?

You can identify windings by checking for continuity using a multimeter.

If you have a signal generator and a 'scope, you can estimate turns ratios
by injecting a small test signal; if not, I would say the OP has the best
idea. The wire guage may also give you a clue: the high-voltage winding is
probably finer wire.

Also, maybe someone knows some cute trick to removing them from the
circuit board? There's a lot of pins and they are soldered in pretty
securely.

I prefer de-soldering wick e.g. Servisol Soldamop. It just soaks up all the
solder like magic leaving the area completely clean except for a very thin
tinning.

 

[Michael Black]

Dominic-Luc Webb (dlwebb@canit.se) writes:

I was about to toss out some old computer monitors, but thought to pull
the flyback transformers for use in some of my high voltage projects.
Question: Is there some simple trick to determine which pins are which?
Maybe there is somewhere online that posts pinouts for more common
flybacks found in more common monitors and TVs?

Also, maybe someone knows some cute trick to removing them from the
circuit board? There's a lot of pins and they are soldered in pretty
securely.

Dominic


Trace the circuit before you remove the tranformers. You should be

able to extract the key pins that way, and all of it if you want to
expend the time. Sometimes when tracing it helps to have a sample
schematic, so you have a general idea of what you will be looking at.
Figure out the driving circuit, indeed you may want to extract some of
the driving circuit as parts, and the rest sort of falls into place (or you
may not even care about since there'll be various lower voltage windings
you don't care about).

Micahel

 

[Dominic-Luc Webb]

On 4 Jan 2005, Michael Black wrote:

Dominic-Luc Webb (dlwebb@canit.se) writes:
I was about to toss out some old computer monitors, but thought to pull
the flyback transformers for use in some of my high voltage projects.
Question: Is there some simple trick to determine which pins are which?
Maybe there is somewhere online that posts pinouts for more common
flybacks found in more common monitors and TVs?

Also, maybe someone knows some cute trick to removing them from the
circuit board? There's a lot of pins and they are soldered in pretty
securely.

Dominic


Trace the circuit before you remove the tranformers. You should be
able to extract the key pins that way, and all of it if you want to
expend the time. Sometimes when tracing it helps to have a sample
schematic, so you have a general idea of what you will be looking at.
Figure out the driving circuit, indeed you may want to extract some of
the driving circuit as parts, and the rest sort of falls into place (or you
may not even care about since there'll be various lower voltage windings
you don't care about).

Micahel

Thanks for suggestions and they certainly make sense to me. I am actually
a bit knew to electronics, but have university education. May I ask how
to safely access this section of the board and if you have suggested
books or, even better, online reading that specifies how to safely access
the high voltage section? I suspect there are some commonly understood
ways to go about this.

Dominic