davezawadi (David Stone):
Hi Dave
The symptom is therefore a large current passes through the HDMI screen (which is very thin foil) and it fuses. HDMI with a disconnected screen is not at all reliable, and the fault could damage the Earth referenced power on the cable to the electronics. Somewhere above I think you said there were 4 Ohms between the two ring Earths, which is excessive and cannot be right, I think you just found the 4 Ohms, the bad ring has no Earth to the Steelwork and a significant Earth fault somewhere too. You should find this with a full ring test, and Earth loop measurements, along with testing to find the intermittently faulty piece of equipment. These currents could be circulating Earth current from elsewhere, a clip-on Ammeter will help with that.
Regards
David
Hi,
Yes, someone previously mentioned about the 4 ohms being too high and I immediately realised i'd been a bit flippant about that reading as it is indeed high. I retested it but dropped the socket fronts off and got an improved reading of 1.5 ohms. Still high but maybe not alarm bell high!
Here's a pic of one of the failed leads showing the chip and it's connections. No wires, including any shielding can bypass the chip by the looks of it...
davezawadi (David Stone):
Hi Dave
The symptom is therefore a large current passes through the HDMI screen (which is very thin foil) and it fuses. HDMI with a disconnected screen is not at all reliable, and the fault could damage the Earth referenced power on the cable to the electronics. Somewhere above I think you said there were 4 Ohms between the two ring Earths, which is excessive and cannot be right, I think you just found the 4 Ohms, the bad ring has no Earth to the Steelwork and a significant Earth fault somewhere too. You should find this with a full ring test, and Earth loop measurements, along with testing to find the intermittently faulty piece of equipment. These currents could be circulating Earth current from elsewhere, a clip-on Ammeter will help with that.
Regards
David
Hi,
Yes, someone previously mentioned about the 4 ohms being too high and I immediately realised i'd been a bit flippant about that reading as it is indeed high. I retested it but dropped the socket fronts off and got an improved reading of 1.5 ohms. Still high but maybe not alarm bell high!
Here's a pic of one of the failed leads showing the chip and it's connections. No wires, including any shielding can bypass the chip by the looks of it...
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