No that is not correct. There will be an AC voltage there, from there it
usually goes to a bridge rectifier and onto the rest of the charging
circuit, probably a capacitor and a chip controlling a transistor if its
quite old. My guess is that something has put a short across the transformer
and a thermal fuse inside it has melted to stop it catching fire. Could be
shorted turns, but more likely the bridge rectifiers failed on a mains spike
and trashed it I had this happen to a power supply for a sub woofer a
couple of years ago, but managed to switch it off before death of the
transformer. It just needed a more robust bridge rectifier fitted and a
surge protection mains connection!
Brian

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On 18/05/2019 14:39, D.M. Procida wrote:
Dave Plowman (News) wrote:

In article
,
D.M. Procida wrote:
I have an old B&D cordless drill; the batteries don't charge.

Either the batteries or the charger are faulty.

I've opened up the charger. At the input of the transformer, I measure
240V. At the output, 0V (I'd expect 18V or so).

I assume this means that the transformer itself is broken - at least, I
can't think that anything in the circuit after the transformer could be
responsible.

I haven't desoldered the transformer from the circuit board, but I
guess
that would be a way of being sure.

Is that correct?

No LEDs, etc to tell you what is going on?

The LEDs (charging, fully-charged) are both off. There is no voltage at
the charger's output, which is why I opened it up to find out if I could
where the fault is.


I would not expect an output from the transformer unless there is a load
on it. And the load would be detected by the components on the PCB.



--
Adam