Art Todesco wrote:

trainfan1 wrote:

Steve B wrote:

I got a Malibu 600 watt transformer. Model ML600TW. When I rotate
the on/off knob, it makes the sound of smacking the outer housing
with a stick. A loud audible clank. Then it hums.

When I apply the tester to the bottom connectors, I can't get it to
read anything. Double checked tester with various voltage alkaline
batteries on DC, and they tested fine, so tester is good.

Is this transformer fried? Is the humming normal? Is that clanking
noise normal?

Steve


This is a switching power supply, which requires a load to show an
output w/ a conventional VOM. A scope is needed to see what's really
going on with these.

Rob

I may be wrong, and frequently are, but I don't think any Malibu light
power
units use a switching power supply. They usually, as has been stated, run
simply on the AC output of an old fashioned transformer. But, with that
said, I have seen 12 volt "transformers" for indoor low voltage
lighting, which
do use switching power supplies. So, anything is possible. The
advantage of
the switching power supply is a reduction in size and weight.

That 600 watt transformer, at 12 volts output(600 VA or 45-55 amps),
would be 50+ lbs. if it were NOT a switching power supply.

Rob