Pos or Neg earth.

[andy spain]

Have just recieved the radio i have been after for years,its the original radio fitted to the U.S. spec mk 1 L/C. with the cortina logo. It would have been pos earth,and there is sticker on the back saying that it is "switced "to pos earth when it left the manufacturer. There is no switch/screw on the exterior allowing me to switch the polarity,so before i take it to bits and promtly regret it to look for that switch/screw inside, is there if any way i can tell what it is set at now.

 

[tommy]

I your mk1 converted to -ve earth then Andy? As original a mk1 would be +ve earth and a mk2 -ve earth. If your mk1 has been made -ve earth you could always change it back (repolarise the dynamo and change over the rev counter).
Tommy

 

[Neilsjuke]

Some radios had a ? pin plug and socket that changed the polarity or switch best to open it and check the board polarity .
Neil

 

[andy spain]

When i got the car Tommy it had been in a warehouse for 17 years along with some other old cars,and i reakon where it was moved about,at some stage the battery was put on the wrong way,so the rev counter,regulator ect was all knackerd, when i got it sorted i had it changed to neg earth.
Reading the caution label on the radio,there has to be a switch somewhere that enables me to switch the polarity.
Unfortunatly Neil,i would'nt know what a polarity board looks like,unless i've seen one one star trek.
If i have any doubts i will take it to an auto electrian,took me years to find one in good nik,aint gonna take no chances.

 

[Neilsjuke]

Take to a sparks and he should be able to tell you at a glance just needs to look at the circuit board.
Neil
Or it may be better to have it restored before powering up as caps are easyer to replace when you can read the info off them before they blow.