I think You were quite sucessful in your effort to silence that
transformer! Using a hammer was very creative! I have found that a
hammer is usually not effective way to get into those things, so you
surely had a big hammer. Perhaps it would be safer to buy a new one. For
future reference, you can often silence a noisy transformer with a small
shim or wooden toothpick between the core and the windings. Dont use so
much force that you cause the wires to short out or break. Noisy
transformers can also mean that there is a bad diode or electrical
short. This may cause a safety issue. Repairing "wall warts" or AC/DC
adaptors is seldom worth the cost and is often unsafe.

wrote:

I have no experience with electronics except dabbling with a
multimeter.

I wanted to silence a humming transformer, I read somewhere that
covering it in JB Weld would do the job. But I didn't even get that
far.

I struggled to open it up, in the end I managed it quite 'easily' with
a hammer.

Before even putting on any JB Weld, I put the lid back on it and
plugged it in.

Then I flicked the mains power switch and bang it blew.

I know it was the ACDC adaptor because and not a mains plug fuse
because the power cord still worked in another ACDC adaptor

Is there a way for me to open one of these things without encountering
that?
does anybody know about silencing humming / whining transformers




--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P