Portable Appliance Testing an iMac

[jamesextras]

Hi there,

I have been trying to PAT Test the business iMac's ranging from mid 2007 to 2010 models. But they all keep failing on the earth continuity test's they are providing a reading of either 0.55 or 0.85 in some cases. They should be reading 0.01.

Does anyone know a good earthing point for the probe or come across this issue before and has resolved it. I obviously do not want to take a whole machine apart to find a good earth it would defeat the purpose of the test.

Many Thanks

James

 

[JonathanKo]

Are you talking about grounding the chassis? Anodized aluminum creates a non-conductive protective layer so if you do a continuity test between 2 points on the chassis, it should be negative. One way around this is to scratch the anodizing to get at the actual aluminum since regular aluminum is conductive, but who wants to scratch Apple products on purpose? lol. I have to do this with PV modules sometimes since their frames are anodized aluminum. I don't know of any external test point you can get at on the iMac. I thought that's what the ground wire in the power cable is for.