Re: Silencing a humming transformer ( + ACDC adaptor that blew )

On 1 Mar, 03:00, James Sweet <jamessw...@xxxxxxxxxxx> wrote:
jameshanle...@xxxxxxxxxxx wrote:
On 1 Mar, 01:00, **THE-RFI-EMI-GUY** <rhyol...@xxxxxxxxxxxx> wrote:

Did anyone notice he was using JB Weld epoxy? I think that stuff has
metal particles in it!

I haven't used it yet. I have a few cheap rubbish ACDC adaptors most
or all of which make a noise. I broke one as described, but i'll try
to experiment on the others too.

http://jbweld.net/products/jbstik.php
it says it's an insulator.

I will reply to my post with links to pictures of the transformer.

<snip>

Regardless there's a lot easier epoxies to use. JB Weld is very thick
paste, you can get liquid epoxy resins which will be much easier to pour
into something.-

thanks for the tip, i'll be getting some.
I posted some pictures of the transformer, I can't really get to it..
The copper coils of wire seem to be covered in some yellow thing and
aroudn the whole thing there's this square housing with yellow tape
over it.

But, just to get an idea of where i'd pour the stuff.. if I could.
Here is a picture of another device I once had. The transformer was
'naked'.

It was a power supply card.
http://linitx.com/product_info.php?products_id=397
you can click the image to enlarge it.
Alternatively here it is
http://img72.imageshack.us/img72/38/aazc0.jpg
There were a couple of transformers on it as you can see.

I think if the transformer is shaped like a doughnut. With my AC-DC
adaptor, the wires go round in circles that are sort of parallel with
the PCB. They go round the circumference of the doughnut. (at last I
think that's what they do, i'd have to pull off the housing to get a
better look)

Whereas on the power supply card that I linked to, the wires are sort
of perpendicular to the PCB.

In the case of the power supply card, would I pour liquid epoxy in the
middle. WHat is actually causing the hum? The coils hitting the
doughnut(core?)


I just googled transformer coils core into google images. And got this
amazing picture
http://img.alibaba.com/photo/11498927/Transformer__Coils__Inductor__Line_Filter.jpg
or for the archives
http://img135.imageshack.us/img135/3100/transformercoilsinductooq8.jpg

I see the one in my AC-DC adaptor in that picture. It's second row
from the back. And second , maybe third, from the left !!


.

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