On Wed, 25 Jul 2012 10:59:50 -0700, Bruce L. Bergman (munged human
readable) wrote:

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.

Ay ay, Sir!

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.

Mine can't decide which mode it is in. Sometimes it doesn't even
start whining when charging. Sometimes the oscillation is in step
with the flashing 'charge' light. Sometimes it stops whining at
end of charge, sometimes it continues.

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.

Lost an alternator that way. Next time I jump someone's battery,
I am borrowing all their car keys. (Grumble)

-- Bruce --