Kendrick Digifire 7 and HEQ5 Pro - polarity check

[mickw]

Don't know if either of mine have been wired wrong but....................

At DSC I plugged the dew heater in then rested it on the tripod spreader plate, the dew heater touched centre fixing bolt which blew the fuse.
I assumed that one of the centre pins of the outputs was a bit too long so I shoved tape over all unused outputs.

Just went over everything with a meter.
The casing of the HEQ5 shows Negative 12v
The 2 x permanent power outlets are OK showing 12v pin Positive
The 4 x dew heater outlets are showing 12v pin NEGATIVE
The housing of the Kendrick is OK showing 0 volts.  I've taken it apart and the PCB is isolated from the case and all outputs are connected directly to the PCB, I can't see an easy way of reversing the polarity of the dewheater outlets, which is not really a problem now I'm aware of it - It's still stupid though.

It's possible this affects other brands of kit so you may want to check yours

[The Thing]

Should the casing of the HEQ5 be connected to it's power source? Sounds odd unless they are trying to save a conductor as they do in cars, unlikely. Possibly the problem is with something shorting to the casing in the mount.

[MarkS]

The casing of my EQ6 is connected straight to -ve.
The centre pin of my dew controller (a Rigel, not a Kendrick) is connected straight to +ve

When switched on you wouldn't any connection to come into contact with any part of the mount/legs.

In any case it's clearly something very aware of.  Thanks for drawing it to our attention.

Mark

[The Thing]

Thank goodness my Meade has plastic covers on the forks!

[Fay]

Oh , I hope this will not affect me in any way.................................

[The Thing]

Wrap your legs in clingfilm Fay, that should prevent any unwelcome shorts. 

[Ian]

would that not cause the unwelcome shorts to keep slipping off?