does my Kendrick dew zapper work?

[Robert_T]

Hi All, sometime ago I bought form Canada a standard Kendrick dew zapper with four outlets and fed from 12v DC cid lighter attachment.

I use this to feed a dewshield which has a built in zapper sewn into one end.

I've never felt this has worked very well, but now it seems not to heat up at all.

The Kendrick unit lights up. I've checked the Voltage on each outlet with a multi-meter but can't get a stable reading. It seems to vary a lot and fade to zero from around 3V. I assume these should be straight DC out so I don't know what's going on.

Does anyone know if this is normal or any ideas?

thanks,

Rob

[gbeal]

Rob,
does it get warm to the touch? Not hot, but warm?
Gary

[Robert_T]

Hi Gary, no no perceptible change in temp at all. cheers, Rob

[Dennis]

Hi Rob

The controller box does not output a constant current; AFAIK, there is a 40% duty cycle which I take to mean that it is “switched on” 40% of the time and “switched off” 60% of the time. I am going on memory here for my Mk IV controller.

I once had a 4” dew strap that failed to work after a couple of years. Taking it apart revealed a broken wire inside, near to where the wire exits the Velcro backed heating strip.

When I turn the controller up to Max and connect a dew strip, I can feel the heat on my lips as it heats up – that’s how I test if they are working. My lips are more sensitive to heat than my fingers!

Cheers

Dennis

[Robert_T]

Thanks Dennis,

Ah that helps a lot. Suggests the controller is OK. I'll try the lip technique, though my wife might get jealous:P

I hope there isn't a broken wire as it's well woven in.

cheers,

Rob

[gb_astro]

Hi Rob.

Set the duty cycle to 100% then with 12V in you should
be measuring a constant 12V at the controller output (no load).

If you are way off this there is something wrong with the controller or power supply or your volt meter.

gb.