On 25 Jul 2012 16:27:31 GMT, Winston wrote:
On Wed, 25 Jul 2012 08:32:57 -0700, stans4 wrote:
On Wednesday, July 25, 2012 7:42:42 AM UTC-6, Winston wrote:

My DW9118 charger emits a loud ~10 KHz audible tone when charging a
battery. It didn't use to do that. Anybody else have one of
these?

You could use the old TV repairman's standard fix, toothpicks and
Ambroid glue to keep the windings from shifting. Used to do that with
flyback tranformers when they got too annoying.

Yes, but I'd be happier if the feedback loop was not oscillating like
that.
I see they put a cheapo 1 uF lytic right next to the MOSFET pass element.
What'll you wager it is no longer a 1 uF low - ESR lytic?

So don't sit there whining about it! Go get a new cap and plug in
your soldering station.

And a little whine is a good thing - When it stops whining, it's done
cooking - and you didn't even need to walk over and check on it.

Or it stopped whining too early because it went into "Hot Pack
Shutdown" or Power Line Fault (usually the 12V truck charger, it
doesn't like the starter motor droop) and you DO need to check on it.

-- Bruce --