Top posted for Brian.
Our 14? year old Creda tumble dryer in the garage sometimes make screaming
noises when used. The next time(s) it is used the noise is normal. I do not
understand this.
I once tried to take it apart to check for fluff and gave up as it was a
nightmare. I did the best I could with a Dyson sucking the fluff out.


Brian Gaff wrote:
Hmm, the number of devices I used to run with covers off is in the
hundreds. Of course a lot of the covers inside a boiler are there for
safety and airflow reasons. However if one can localise the vibration
and poke it with a plastic knitting needle to be sure then you can
power it all down and fix it. The most annoying one of these sort of
things was a tumble dryer that squeaked, but only when the covers
were on.That in the end turned out to be just a belt, though to this
day I do not understand why it sounded as it did.

Old age in equipment does many odd things, as does disturbing things
that have been ok for years.

Back in the old days of the first colour TV sets, we had one that
would whistle very loudly sometimes and not others. That turned out
to be a coil on the timebase boared not vibrating at the real
frequency it was using of course, as that is beyond hearing but some
lower frequency agitated by the higher one. A blob of quick setting
araldite fixed it. I'd not want to have been the engineer trying to
remove it from the pcb later on though :-) Brian

RJH brought next idea :
Couldn't see anything obvious. Some wire looms loose. But it'd take
a lot to create that sound. Another step is as you suggest - fire
up without the cover on - building up to that :-)

You will be OK with just the outer cosmetic, none sealed panels off.
Under that is a second room sealed panelling system, with out which
it should never be run.